it has been argued that the degree of asymmetry in bilateral features is one of the fundamental factors underlying human attractiveness . one such study was done by goel et al . to detect the asymmetries and their correlation with malocclusions in karnataka population . they concluded that there was decrease in magnitude of the asymmetry as higher regions of craniofacial skeleton was approached . studies conducted by profitt and severt assessing facial asymmetries in orthodontic patients clinically found a prevalence ranging from 12% to 37% in north carolina , united states , 23% in belgium , and 21% in hong kong . performed a similar study to evaluate the size and shape - related craniofacial skeletal asymmetries , and concluded wider left side of the face and a shorter vertical dimension on the right side . kowner in a classic experiment on the perception of attractiveness based on symmetry conducted in japan concluded that limited asymmetry may be simply more aesthetic , regardless of its function . fong et al . in a study conducted in taiwan concluded that 68% of the study population showed chin deviation to the left side and ( 32% ) to the right side . in another study , anistoroaei et al . concluded that facial asymmetry was present in 4.7% of patients ; they also concluded that a significant correlation was evidenced between facial asymmetry and type of malocclusions , age , and type of dentition . while most of the studies have concluded that no quantitative differences in different types of measurements of face exists in relation to face , some studies , such as the one conducted by ercan et al . , concluded that the number of significantly asymmetric linear distances between the two halves of the face was greater in females than that in males . cheng in his review concluded the symmetry of the face is highly influenced by soft tissue landmarks . the purpose of the present study was to evaluate the prevalence of skeletal facial asymmetry using frontal cephalograms and frontal photographs among the adults of tirupati , andhra pradesh , hitherto assessing the correlation of skeletal facial asymmetry and soft tissue facial asymmetry as well as to assess the gender differences in the prevalence of facial asymmetry . a total of 100 residents ( 50 males and 50 females ) of tirupati , andhra pradesh in the age group of 1825 years were selected for the study through randomized sampling [ tables 1 and 2 ] . before commencement of the study , sample size and mean age group of the sample mean age group of the study groups the inclusion criteria were clinically acceptable facial symmetry , presence of full complement of teeth , no history of pathology / trauma / surgical intervention or orthodontic treatment , and no congenital abnormalities in the maxillofacial region . the sample size was calculated using the following formula : e = z/2/n facial photographs were taken with a canon power shot a 650 is camera and by the same photographer . participants were made to stand and assume natural head position , so that their frankfurt horizontal ( fh ) planes will be parallel to the floor . the analysis for assessment of transverse frontal facial asymmetry was done by using frontal asymmetry analysis suggested by grummons [ figure 1 ] . for subjective evaluation , frontal photographs were assessed by using composite photographs . list of land marks used in this study this is a vertical reference line . according to grummons , mid sagittal reference ( msr ) closely follows visual plane formed by subnasale and the midpoint between the eyes and eyebrows , and hence msr was selected as the key reference line [ figures 2 and 3 ] . ( a ) line from midpoint of z plane through ans , ( b ) line from midpoint of z plane through fr - fr line four planes were drawn to show the degree of parallelism and symmetry of the facial structures . three planes connected the medial aspects of the zygomatic frontal sutures ( zz ) , the centers of the zygomatic arches ( za ) , and the medial aspects of the jugal processes ( j ) . another plane was drawn at menton parallel to the z plane [ figure 4 ] . two triangles ( right and left ) were formed by joining the ag , me , and co points on both sides , representing the mandibular morphology . the linear measurements for all the three sides of the triangles were recorded along with the measurements of the angles formed by joining co , go , and me points on both sides [ figure 5 ] . mandibular morphology the vertical offset as well as the linear distance was measured from msr to co , nc , j , ag , go , and me were measured . the linear distance to msr from the land marks co , nc , j , ag , go , u , l , and me was calculated for paired structures , the distance away from the midline was determined for both landmarks , and the difference between the distances was calculated . for unpaired points , the horizontal distance to the midline will be determined [ figure 6 ] . frontal photographs of the participants were taken and each photograph is divided into left and right sides and left half of the face and its mirror image are joined together and similarly right half of the face and its mirror image were joined to form two facial composites , i.e. , l - l ( left composite ) and r - r ( right composite ) . facedness of the sample or population refers to the side with highest total prevalence [ figure 7 ] . according to grummons , mid sagittal reference ( msr ) closely follows visual plane formed by subnasale and the midpoint between the eyes and eyebrows , and hence msr was selected as the key reference line [ figures 2 and 3 ] . ( a ) line from midpoint of z plane through ans , ( b ) line from midpoint of z plane through fr - fr line four planes were drawn to show the degree of parallelism and symmetry of the facial structures . three planes connected the medial aspects of the zygomatic frontal sutures ( zz ) , the centers of the zygomatic arches ( za ) , and the medial aspects of the jugal processes ( j ) . another plane was drawn at menton parallel to the z plane [ figure 4 ] . two triangles ( right and left ) were formed by joining the ag , me , and co points on both sides , representing the mandibular morphology . the linear measurements for all the three sides of the triangles were recorded along with the measurements of the angles formed by joining co , go , and me points on both sides [ figure 5 ] . the vertical offset as well as the linear distance was measured from msr to co , nc , j , ag , go , and me were measured . the linear distance to msr from the land marks co , nc , j , ag , go , u , l , and me was calculated for paired structures , the distance away from the midline was determined for both landmarks , and the difference between the distances was calculated . for unpaired points , the horizontal distance to the midline will be determined [ figure 6 ] . frontal photographs of the participants were taken and each photograph is divided into left and right sides and left half of the face and its mirror image are joined together and similarly right half of the face and its mirror image were joined to form two facial composites , i.e. , l - l ( left composite ) and r - r ( right composite ) . facedness of the sample or population refers to the side with highest total prevalence [ figure 7 ] . the data were statistically collected and tabulated in microsoft excel . the data was stastically analyzed using the statistical package for the social sciences ( spss ) version 16.0 program statistical analysis package software . independent t - test was used to find the differences between different measurements and the significance in the measurements of the right and left side dimensions , if any . the data was checked for the normal distribution using t - statistics and then the correlation coefficients between the various parameters were calculated using pearson 's correlation to determine which would produce a higher value . table 3 shows the bilateral facial widths observed at z , co , za , j , nc , ag , go distances , as total widths , right side , and left side . table 4 shows total bilateral facial widths observed at z , co , za , j , nc , ag , and go for males . table 5 shows total bilateral facial widths observed at z , co , za , j , nc , ag , and go for females . bilateral facial widths observed at z , co , za , j , nc , ag , and go distance as total width , right side , and left side bilateral facial widths observed at z. co , za , j , nc , ag , and go for males bilateral facial widths observed at z. co , za , j , nc , ag , and go for females the results showed statistically significant difference between the mean z , co , za , j , nc , ag , and go values of males and females ( p < 0.01 ) . the difference between the right and left sides were statistically insignificant ( p > 0.01 ) . the test revealed that only co distance was statistically significant ( p < 0.01 ) . the means and standard deviation of vertical distances from the right and left z , co , za , j , nc , ag , and go to the msr on both groups are shown in table 6 . vertical offset of z. co , za , j , nc , ag , and go tables 68 shows bilateral widths of co - go , go - me , co - me , and gonial angle to assess the mandibular morphology ( p < 0.05 ) . there was statistically significant difference between the mean co - me value and gonial angle of the right and left sides . total bilateral widths and gonial angle to assess the mandibular morphology bilateral widths and gonial angle to assess the mandibular morphology in males table 9 shows the bilateral widths and gonial angle to assess the mandibular morphology in females . the results were statstiscally significant for the coronoid and menton distance and the coronoid gonion and menton distance . bilateral widths and gonial angle to assess the mandibular morphology in females table 10 shows mandibular offset at menton . menton deviated to the left side in 55% ( 2.6  1.4 mm ) and deviated to right in 3% ( 1.6  0.28 mm ) . in 58% males deviation was towards left ( 2.4  1.02 ) and towards right 4% ( 1.7  0.3 mm ) . mean angles formed by z , za , j , me , and occlusal planes with msr shows that there was no statistically significant canting . parallelism of facial structures tables 12 and 13 show the sidedness of the face by subjective evaluation of composite photographs of 100 participants . out of a total of 100 participants , it was observed that 81 were right faced ( r - r ) and 19 were left faced . thirty - nine males were observed to be right faced ( r - r ) and 11 were observed to be left faced ( l - l ) . whereas in females , 42 were observed as right faced ( r - r ) and 8 were observed to be left faced ( l - l ) . therefore , in males and females , facedness is towards the right , and female faces were more right faced than males ( p > 0.01 ) . table 3 shows the bilateral facial widths observed at z , co , za , j , nc , ag , go distances , as total widths , right side , and left side . table 4 shows total bilateral facial widths observed at z , co , za , j , nc , ag , and go for males . table 5 shows total bilateral facial widths observed at z , co , za , j , nc , ag , and go for females . bilateral facial widths observed at z , co , za , j , nc , ag , and go distance as total width , right side , and left side bilateral facial widths observed at z. co , za , j , nc , ag , and go for males bilateral facial widths observed at z. co , za , j , nc , ag , and go for females the results showed statistically significant difference between the mean z , co , za , j , nc , ag , and go values of males and females ( p < 0.01 ) . the difference between the right and left sides were statistically insignificant ( p > 0.01 ) . the test revealed that only co distance was statistically significant ( p < 0.01 ) . the means and standard deviation of vertical distances from the right and left z , co , za , j , nc , ag , and go to the msr on both groups are shown in table 6 . vertical offset of z. co , za , j , nc , ag , and go tables 68 shows bilateral widths of co - go , go - me , co - me , and gonial angle to assess the mandibular morphology ( p < 0.05 ) . there was statistically significant difference between the mean co - me value and gonial angle of the right and left sides . total bilateral widths and gonial angle to assess the mandibular morphology bilateral widths and gonial angle to assess the mandibular morphology in males table 9 shows the bilateral widths and gonial angle to assess the mandibular morphology in females . the results were statstiscally significant for the coronoid and menton distance and the coronoid gonion and menton distance . bilateral widths and gonial angle to assess the mandibular morphology in females table 10 shows mandibular offset at menton . menton deviated to the left side in 55% ( 2.6  1.4 mm ) and deviated to right in 3% ( 1.6  0.28 mm ) . in 58% males deviation was towards left ( 2.4  1.02 ) and towards right 4% ( 1.7  0.3 mm ) . mean angles formed by z , za , j , me , and occlusal planes with msr shows that there was no statistically significant canting . parallelism of facial structures tables 12 and 13 show the sidedness of the face by subjective evaluation of composite photographs of 100 participants . out of a total of 100 participants , it was observed that 81 were right faced ( r - r ) and 19 were left faced . thirty - nine males were observed to be right faced ( r - r ) and 11 were observed to be left faced ( l - l ) . whereas in females , 42 were observed as right faced ( r - r ) and 8 were observed to be left faced ( l - l ) . therefore , in males and females , facedness is towards the right , and female faces were more right faced than males ( p > 0.01 ) . this has been verified and stressed upon by many researchers dating back from   shah and joshi and peck et al . a posteronterior cephalometric radiographic study of 100 participants with pleasing symmetrical faces and normal occlusions was conducted with the objective of evaluating the extent of facial asymmetry . frontal photographs were obtained and studied for subjective evaluation of facial asymmetry seen in the selected tirupati population . the frontal analysis suggested by grummons was used to assess the patients for the transverse ( skeletal ) facial asymmetries as it provides clinically relevant information regarding specific locations and amounts of facial asymmetry and measures mandibular morphology , which can be seen to play a major role in asymmetries . the results of the present study [ table 1 ] showed that the bilateral total widths of z , co , nc , ag , and co on the right side was greater than those on the left side , however , the difference was statistically insignificant except for co. only the co distance was statistically significant ( p < 0.01 ) . this shows that asymmetry was present more in the condylar region and towards right side . the difference between the right and left side mean absolute asymmetry for z , nc , abd j distances are less than those for co , ag , and go . none of the studies on facial asymmetry measured vertical offsets . in the present study , vertical offsets of z. co , za , j , nc , ag , and go were also measured and no statistical difference between males and females ( p > 0.01 ) . for the assessment of the mandibular morphology , co - ag , co - me , and ag - me and gonial angle were statistically analyzed [ table 2 ] . the possible cause of asymmetry in gonial angle are asymmetry functional patterns such as unilateral chewing patterns , muscular atrophies , etc . it shows that gonial angle is the only region where the right side is larger than the left side . mandibular length ( co - me ) and gonial angle ( co - go , me ) showed statistically significant difference between the right and left sides , with right side being larger in total as well as in males and females . this is in accordance with a similar study conducted by shah and joshi and azevedo et al . chin deviations in our study showed a left sidedness , which is in agreement with findings of severt and profit . the high incidence of chin deviation may be due to the asymmetries of mandibular length , which also showed high incidence . the possible reason given by woo is the increased size of the right hemisphere of brain . the mean values obtained for the angles formed by the various planes used in this analysis were more or less parallel to each other . these findings are in agreement with ricketts and grummons . in our study on composite photographic analysis , mild asymmetry was observed both in males and females with males having wider faces than females . me - co length showed statistically significant right sidedness in total ( p < 0.01 ) ; males ( p < 0.05 ) , females ( p < 0.05 ) . the findings in our study are in concordance with many studies , however , left side laterality was observed in few studies . seventy - eight percent of males and 88% females were observed as right faced ( r - r ) on composite photographic analysis . the findings in our study are in concordance with those carried out by farkas and cheung , and ferrario virgilio et al . generally , skeletal deviation must be greater than 4 mm to render the asymmetry visible in an individual 's face . therefore , other authors consider an asymmetrical face as having bone deviations equal to or greater than 2 mm . this might be the major drawback of the study because the present study utilized photographs also for determining the depth of facial asymmetries . other main limitations of the study are the errors in identifying the anatomical landmarks in posteroanterior cephalograms due to superimposition of many craniofacial structures . a three - dimensional topographic study or cone - beam computed tomography ( cbct ) complete cbct software to identify different landmarks three dimensionally could also be helpful in marking the facial asymmetries . other advanced means such as the use of stereophotogrammetry , ( three - dimensional photography ) or quantifying facial soft tissue asymmetry by a three - dimensional imaging - based method , or use of the weibull distribution - based comparison of a person 's asymmetry with respect to a large sample of symmetrical faces would be more accurate . composite photographs of hundred participants revealed that facedness is towards right , however , this laterality was not statistically significant . both posteroanterior cephalograms and composite photographs showed right - sided laterality . in the evaluation for an orthodontic treatment , asymmetry of the face should be considered and may only be noticed with a morphometric analysis . the present data may be of use for future clinical studies , but studies with larger sample at different geographical locations are warranted . a classification for asymmetry based on the data collected for the asian group would be useful for future research on this subject . the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s ) has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal . the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed . the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s ) has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal . the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .