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Facial asymmetry, the right-side dominance: A retrospective analysis of 315 consecutive series of patients

Open AccessPublished:November 10, 2022DOI:https://doi.org/10.1016/j.jpra.2022.11.001

      Abstract

      Background

      Asymmetry of the face is a common finding that had been discussed in a variety of fields including art, poetry, philosophy and medicine. In the surgical literature, facial asymmetry in general and the laterality of this observation, described mostly as a casual note, without profound discussion. In our study, we hypothesis that, facial asymmetry in the normal unbiased population has a unique laterality appearance.

      Patients and methods

      A consecutive series of 315 patients included in the study, all had anterior facial digital pictures taken in the same technique and loaded on Image J Software™. Four measurements were taken from the midline, to right and left sides; in the middle face to the Zygoma point and in the lower face to Gonion point. The results given by pixels were loaded on excel sheet, office 2016 software™, processed and analyzed by Spss software™.

      Results

      Using the paired T-test. Middle and lower third of the face in the right side had a significant dominance size wise with p-value < 0.019 and < 0.039 respectively.

      Conclusion

      Our study results support our main hypothesis and strongly demonstrate right side, size wise, dominance in the middle and lower face.

      Keywords

      Introduction

      Facial appearance, size, shape, beauty, symmetry, and harmony have been discussed profoundly in the literature for over 2000 years
      • Farhad B N
      Facial aesthetics: concepts and clinical diagnosis facial aesthetics: concepts and clinical diagnosis.

      Plato. Symposium. London: Penguin Classics, 2003.

      Aristotle. The Metaphysics. London: Penguin Classics, 2004.

      Plato. Protagoras. Oxford: Oxford University Press, 2002.

      . However, a well-documented research work, did not began till the Renaissance era, when Leonardo da Vinci elucidated his theories and ideas in a vast number of manuscripts regarding human proportions and his quest for the ideal facial proportions
      • Leonardo da Vinci Kemp M.
      The marvelous Works of Nature and Man.
      ,
      • Vinci Leonardo da
      Notebook of a Genius.
      . Great number of prominent Italian art masters made enormous contributions to the understanding of human beauty and symmetry, such as Michelangelo and Raphael; continued in the last 300 years with writers, philosophers, and scholars, emphasized the rational and scientific knowledge which led to the neoclassical canon's proportions
      • Farhad B N
      Facial aesthetics: concepts and clinical diagnosis facial aesthetics: concepts and clinical diagnosis.
      .
      In the modern scientific and medical literature, facial appearance was thoroughly investigated, studied, and presented in variety of publications, all include the inevitable knowledge that all of us, the humans, have some degree of asymmetry
      • Peck S
      • Peck L
      • Kataja M.
      Skeletal asymmetry in esthetically pleasing faces.
      • Haraguchi S
      • Takada K
      • Yasuda Y.
      Facial asymmetry in subjects with skeletal Class III deformity.
      • Haraguchi S
      • Iguchi Y
      • Takada K.
      Asymmetry of the face in orthodontic patients.
      • Shah SM
      • Joshi MR.
      An assessment of asymmetry in the normal craniofacial complex.
      • Vig PS
      • Hewitt AB.
      Asymmetry of the human facial skeleton.
      • Chebib FS
      • Chamma AM.
      Indices of craniofacial asymmetry.
      . The asymmetry was measured using different reference structures, from skeleton measurements as in the extensive innovative work of Farkas on the cephalometric studies, continued by variety of publications at all surface levels
      • Farkas LG.
      Anthropometry of the head and face in medicine.
      • Farkas LG
      • Cheung G.
      Facial asymmetry in healthy North American Caucasians. An anthropometrical study.
      • Farkas LG
      • Forrest CR
      • Litsas L.
      Revision of neoclassical facial canons in young adult Afro-Americans.
      .
      Over the last 20 years, the authors examined facial structure in thousands of patients and raised the hypothesis that facial asymmetry is not arbitrary but rather had unique repetitive laterality. The purpose of this study was to explore the clinical observation by the authors, means that facial asymmetry in the normal unbiased population has a unique repetitive pattern between right and left, and discuss some implications of the findings.

      Materials and methods

      A consecutive series of 500 patient frontal facial pictures treated by the surgeons for variety of facial procedures, enter the study. The pictures were taken by digital Nikon camera with 60 mm macro lens from the same distance. Any patients, that according to the medical file, the chief complain was facial asymmetry, had prior injections for facial contouring enhancement during the last 12 months, prior facial surgeries, significant dental, or orthodontic work performed and or significant\morbid obesity; were excluded off the study. The pictures were loaded on Mac computer and measuring performed by using an Image-J software™. The Image-J software transformed the digital camera data into measurable pixels, means that accurate measurement can be applied without the fear that slight distance difference between the object and the lens may alter the measurements. The midline divider was a straight line drawn between Glabella – Nasion – SubNasale – Menton, and the reference points were right and left Zygoma points, (1 and 2 respectively) and right and left Gonion points (3 and 4 respectively) - see figure one, all can easily be found, draw, and marked on frontal picture with minimal (if at all) bias or question, whether is the right point. Following, four measurements that were taken in 90 degrees to the midline divider, measured by pixels, loaded on excel sheet office 2016 software™ converted the data into Spss software™ allow analyzing the data by our statistical consultant. (Figs. 1 and 6)
      Figure 1
      Figure 1Facial landmarks .1,2 Zygoma right and left respectively. 3,4 Gonion right and left respectively.

      Results

      Following implementation of all the exclusions criteria, 315 patients enter the study process; 250 females and 65 males with age range from 21 – 65 with 34 years old on average. Using the paired T-test, in the middle and lower third of the face, the right side has a significant definitive dominance with p-value < 0.019 and < 0.039 respectively. (See Table 1). Figure 2, Figure 3, Figure 4, Figure 5 demonstrate few patients measurements.
      Table 1Facial measurements in pixels included in multivariate analysis.
      DistanceMean (pixels) +/- SDP - Value
      Midline - Right Zygoma
      • Farhad B N
      Facial aesthetics: concepts and clinical diagnosis facial aesthetics: concepts and clinical diagnosis.
      738.60 +/- 249.53P < 0.019
      Midline – Left Zygoma

      Plato. Symposium. London: Penguin Classics, 2003.

      692.81 +/- 239.15
      Midline – Right Gonion

      Aristotle. The Metaphysics. London: Penguin Classics, 2004.

      570.47 +/- 209.72P < 0.039
      Midline – Left Gonion

      Plato. Protagoras. Oxford: Oxford University Press, 2002.

      536.58 +/- 202.36
      Figure 2
      Figure 2( – 6). Frontal Picture of 5 patients included in the study.
      Figure 3
      Figure 3( – 6). Frontal Picture of 5 patients included in the study.
      Figure 4
      Figure 4( – 6). Frontal Picture of 5 patients included in the study.
      Figure 5
      Figure 5( – 6). Frontal Picture of 5 patients included in the study.
      Figure 6
      Figure 6( – 6). Frontal Picture of 5 patients included in the study.

      Discussion

      Asymmetry of the face is a common finding that discussed in a variety of fields including art, poetry, philosophy, and medicine
      • Farhad B N
      Facial aesthetics: concepts and clinical diagnosis facial aesthetics: concepts and clinical diagnosis.
      ,
      • Farkas LG.
      Anthropometry of the head and face in medicine.
      • Farkas LG
      • Cheung G.
      Facial asymmetry in healthy North American Caucasians. An anthropometrical study.
      • Farkas LG
      • Forrest CR
      • Litsas L.
      Revision of neoclassical facial canons in young adult Afro-Americans.
      • Gorney M
      • Harries T.
      The preoperative and postoperative consideration of natural facial asymmetry.
      . In the surgical literature, the facial asymmetry was described mostly as an anatomical note without profound discussion of the laterality
      • Peck S
      • Peck L
      • Kataja M.
      Skeletal asymmetry in esthetically pleasing faces.
      • Haraguchi S
      • Takada K
      • Yasuda Y.
      Facial asymmetry in subjects with skeletal Class III deformity.
      • Haraguchi S
      • Iguchi Y
      • Takada K.
      Asymmetry of the face in orthodontic patients.
      • Shah SM
      • Joshi MR.
      An assessment of asymmetry in the normal craniofacial complex.
      • Vig PS
      • Hewitt AB.
      Asymmetry of the human facial skeleton.
      • Chebib FS
      • Chamma AM.
      Indices of craniofacial asymmetry.
      . Although in variety of studies we could find casual notes about the laterality including the right-side dominance, but none discussed it in depth
      • Ferrario VF
      • Sforza C
      • Jr Miani A
      • Serrao G
      A three-dimensional evaluation of human facial asymmetry.
      • Ferrario VF
      • Sforza C
      • Ciusa V
      • Dellavia C
      • Tartaglia GM.
      The effect of sex and age on facial asymmetry in healthy subjects: a cross-sectional study from adolescence to mid-adulthood.
      • Peck H
      • Peck S.
      A concept of facial esthetics.
      .
      In our study, midline was based on well-established external landmarks connected by straight line, which can easily be found and marked on frontal picture with minimal if at all bias or question where is the right point
      • Hammond P
      • Forster-Gibson C
      • Chudley AE
      • et al.
      Face-brain asymmetry in autism spectrum disorders.
      . The facial width in the middle and the lower third of the face were measured by connecting the four landmarks points in 90 degree to the midline
      • Farkas LG.
      Anthropometry of the head and face in medicine.
      • Farkas LG
      • Cheung G.
      Facial asymmetry in healthy North American Caucasians. An anthropometrical study.
      • Farkas LG
      • Forrest CR
      • Litsas L.
      Revision of neoclassical facial canons in young adult Afro-Americans.
      . The data obtained was loaded and processed by using Image-J software™ and the data (in pixels) inserted into an excel sheet, office 2016 ™ and analyzed with Spss software™
      • Schneider CA
      • Rasband WS
      • Eliceiri KW.
      NIH Image to Image J: 25 years of image analysis.
      . The statistical analysis shows clearly and significantly and is in line with our hypothesis of right-side lateralization dominance. We found that the right side is dominant over the left side, size wise in both the middle face (M right= 738.60, SD=249.53, M left= 692.81, SD=239.15, t (315) = 2.35, p<0.019) and the lower face (M right= 570.47, SD=209.72, M left= 536.58, SD=202.36, t(315) = 2.06, p<0.039). These finding to our best knowledge were not discussed nor published ever in the medical English literature; however, in the artistic literature the left side get dominance over the right, without statistical significance
      • Mcmanus IC
      • Humphrey NK
      Turning the left cheek.
      • McLaughlin JP
      • Murphy KE.
      Preference for profile orientation in portraits.
      • Powell WR
      • Schirillo JA.
      Hemispheric laterality measured in Rembrandt's portraits using pupil diameter and aesthetic verbal judgements.
      . We would like to note that our study contains facial measurements of adults only, to eliminate the possibility of post maturation changes
      • Hunter CJ.
      The correlation of facial growth with body height and skeletal maturation at adolescence.
      . In the non-English literature, Busse which analyzed visually facial photographs did not find either side to be dominant over the other
      • Farkas LG
      • Cheung G.
      Facial asymmetry in healthy North American Caucasians. An anthropometrical study.
      .
      Facial appearance and symmetry are the outer reflection of the inner structures, the skeleton, including teeth, muscles of mastication, muscles of expression, subdermal fat and the Bichat fat pad. As we observe from vertex caudally, we have more structures involved in contouring the outer shape. At the zygoma point we have bone, muscle and fat; and in the gonion reference point we add to the equation the teeth and the occlusion, which are more subjected to dental changes, so it reflects more diversity in the measurement; and as a result we notice a reduction in the power of the statistical power in the right laterality dominance (p < 0.039) comparing to the middle face (p < 0.019)
      • Haraguchi S
      • Takada K
      • Yasuda Y.
      Facial asymmetry in subjects with skeletal Class III deformity.
      ,
      • Baek C
      • Paeng JY
      • Lee JS
      • Hong J.
      Morphologic evaluation and classification of facial asymmetry using 3-dimensional computed tomography.
      ,
      • Liu MT
      • Iglesias RA
      • Sekhon SS
      • et al.
      Factors contributing to facial asymmetry in identical twins.
      .
      The soft tissue components contain skin, fat, and muscle, has various ethnic differences, but since all our patients were Caucasians and we exclude significant obese patients, these three elements have minimal effects on results deviation
      • Hwang HS
      • Kim WS
      • McNamara Jr, JA.
      Ethnic differences in the soft tissue profile of Korean and European-American adults with normal occlusions and well-balanced faces.
      . Although studies suggest that the left hemi-face is more expressive of emotions, means the expression muscles in the left side are more active, it did not over roll our findings of right-side dominance size wise
      • Haraguchi S
      • Iguchi Y
      • Takada K.
      Asymmetry of the face in orthodontic patients.
      ,
      • Sackeim HA
      • Gur RC
      • Saucy MC.
      Emotions are expressed more intensely on the left side of the face.
      ,
      • Indersmitten T
      • Gur RC.
      Emotion processing in chimeric faces: hemispheric asymmetries in expression and recognition of emotions.
      . In 1938, Fink published his study entitled “the right eye dominance”, does it impose unnoticed tilt of the face? We carefully examine the frontal pictures and could not find any findings to support it
      • Fink WH.
      The dominant eye.
      . Does people in general uses the right side for chawing and has a larger mastication muscle in the right side was not well discussed in the literature yet
      • Tay DK.
      Physiognomy in the classification of individuals with a lateral preference in mastication.
      . We did not find in our study results any relevance to gender identity, which consistent with Lambros finding related to facial aging
      • Lambros V.
      Facial Aging: A 54-Year, Three-Dimensional Population Study.
      . The relevance of potential exogenous contributors to facial asymmetry, such as sleep position, stress, smoking, alcohol consumption and tension headache were not currently studied
      • Liu MT
      • Iglesias RA
      • Sekhon SS
      • et al.
      Factors contributing to facial asymmetry in identical twins.
      . Our study analyzed our own crude data as appears in patients files. In the effort to explain the findings we did extensive search in the literature even for possible factors such as right or left handedness and new genetic published studies; and could not find any solid relation to the right-side dominance size wise we found.
      In conclusion, our study results, strongly support right side size dominance at the middle and lower face, findings that can help with patient's interaction by providing them solid information regarding the inherited asymmetry that we all have; and help in the process of explaining the expected results of facial procedures including major and minor surgical procedures, fillers and other procedures since we all have some degree of inherited lateral asymmetry; further studies will be helpful to elucidate the factors induces our findings.

      Funding

      None.

      Ethical approval

      Not required.
      We declare that patients consent for photo publication in the manuscript was given in writing without exception.

      Conflict of interest

      None declared.

      References

        • Farhad B N
        Facial aesthetics: concepts and clinical diagnosis facial aesthetics: concepts and clinical diagnosis.
        Wiley-Blackwell, London2011
      1. Plato. Symposium. London: Penguin Classics, 2003.

      2. Aristotle. The Metaphysics. London: Penguin Classics, 2004.

      3. Plato. Protagoras. Oxford: Oxford University Press, 2002.

        • Leonardo da Vinci Kemp M.
        The marvelous Works of Nature and Man.
        Oxford University Press, Oxford2006
        • Vinci Leonardo da
        Notebook of a Genius.
        Powerhouse Publishing, Milan2001
        • Peck S
        • Peck L
        • Kataja M.
        Skeletal asymmetry in esthetically pleasing faces.
        Angle Orthod. 1991; 61 (43-8)
        • Haraguchi S
        • Takada K
        • Yasuda Y.
        Facial asymmetry in subjects with skeletal Class III deformity.
        Angle Orthod. 2002; 72: 28-35
        • Haraguchi S
        • Iguchi Y
        • Takada K.
        Asymmetry of the face in orthodontic patients.
        Angle Orthod. 2008; 78 (421- 6)
        • Shah SM
        • Joshi MR.
        An assessment of asymmetry in the normal craniofacial complex.
        Angle Orthod. 1978; 48: 141-148
        • Vig PS
        • Hewitt AB.
        Asymmetry of the human facial skeleton.
        Angle Orthod. 1975; 45: 125-129
        • Chebib FS
        • Chamma AM.
        Indices of craniofacial asymmetry.
        Angle Orthod. 1981; 51: 214-226
        • Farkas LG.
        Anthropometry of the head and face in medicine.
        Elsevier, New York1981
        • Farkas LG
        • Cheung G.
        Facial asymmetry in healthy North American Caucasians. An anthropometrical study.
        Angle Orthod. 1981; 51: 70-77
        • Farkas LG
        • Forrest CR
        • Litsas L.
        Revision of neoclassical facial canons in young adult Afro-Americans.
        Aesthetic Plast Surg. 2000; 24: 179-184
        • Gorney M
        • Harries T.
        The preoperative and postoperative consideration of natural facial asymmetry.
        Plast Reconstr Surg. 1974; 54: 187-191
        • Ferrario VF
        • Sforza C
        • Jr Miani A
        • Serrao G
        A three-dimensional evaluation of human facial asymmetry.
        J Anat. 1995; 186: 103-110
        • Ferrario VF
        • Sforza C
        • Ciusa V
        • Dellavia C
        • Tartaglia GM.
        The effect of sex and age on facial asymmetry in healthy subjects: a cross-sectional study from adolescence to mid-adulthood.
        J Oral Maxillofac Surg. 2001; 59: 382-388
        • Peck H
        • Peck S.
        A concept of facial esthetics.
        Angle Orthod. 1970; 40: 284-318
        • Hammond P
        • Forster-Gibson C
        • Chudley AE
        • et al.
        Face-brain asymmetry in autism spectrum disorders.
        Mol Psychiatry. 2008; 13: 614-623
        • Schneider CA
        • Rasband WS
        • Eliceiri KW.
        NIH Image to Image J: 25 years of image analysis.
        Nature Methods. 2012; 9 (671-5)
        • Mcmanus IC
        • Humphrey NK
        Turning the left cheek.
        Nature. 1973; 243: 271-272
        • McLaughlin JP
        • Murphy KE.
        Preference for profile orientation in portraits.
        Empir Stud Arts. 1994; 12: 1-7
        • Powell WR
        • Schirillo JA.
        Hemispheric laterality measured in Rembrandt's portraits using pupil diameter and aesthetic verbal judgements.
        Cogn Emot. 2011; 25: 868-885
        • Hunter CJ.
        The correlation of facial growth with body height and skeletal maturation at adolescence.
        Angle Orthod. 1966; 36: 44-54
        • Baek C
        • Paeng JY
        • Lee JS
        • Hong J.
        Morphologic evaluation and classification of facial asymmetry using 3-dimensional computed tomography.
        J Oral Maxillofac Surg. 2012; 70: 1161-1169
        • Liu MT
        • Iglesias RA
        • Sekhon SS
        • et al.
        Factors contributing to facial asymmetry in identical twins.
        Plast Reconstr Surg. 2014; 134: 638-646
        • Hwang HS
        • Kim WS
        • McNamara Jr, JA.
        Ethnic differences in the soft tissue profile of Korean and European-American adults with normal occlusions and well-balanced faces.
        Angle Orthod. 2002; 72: 72-80
        • Sackeim HA
        • Gur RC
        • Saucy MC.
        Emotions are expressed more intensely on the left side of the face.
        Science. 1978; 202: 434-436
        • Indersmitten T
        • Gur RC.
        Emotion processing in chimeric faces: hemispheric asymmetries in expression and recognition of emotions.
        J Neurosci. 2003; 23: 3820-3825
        • Fink WH.
        The dominant eye.
        Arch Ophthalmol. 1938; 19: 555-582
        • Tay DK.
        Physiognomy in the classification of individuals with a lateral preference in mastication.
        J Orofac Pain. 1994; 8: 61-72
        • Lambros V.
        Facial Aging: A 54-Year, Three-Dimensional Population Study.
        Plast Reconstr Surg. 2020; 145: 921-928