FREE ELECTRONIC LIBRARY - Dissertations, online materials

Pages:   || 2 | 3 | 4 |

«Symmetry 2010, 2, 1925-1944; doi:10.3390/sym2041925 OPEN ACCESS symmetry ISSN 2073-8994 Article Three-Dimensional ...»

-- [ Page 1 ] --

Symmetry 2010, 2, 1925-1944; doi:10.3390/sym2041925



ISSN 2073-8994



Three-Dimensional Facial Asymmetry in Attractive and Normal

People from Childhood to Young Adulthood

Chiarella Sforza 1,*, Alberto Laino 2, Gaia Grandi 1, Luca Pisoni 1 and Virgilio Ferruccio Ferrario 1

Laboratorio di Anatomia Funzionale dell’Apparato Stomatognatico, Dipartimento di Morfologia

Umana e Scienze Biomediche “Città Studi”, Università degli Studi di Milano, 20122 Milan, Italy;

E-Mails: Gaia.Grandi@gmail.com (G.G.); Luca.Pisoni@studenti.unimi.it (L.P.);

Virgilio.Ferrario@unimi.it (V.F.F.) Dental, Oral, and Maxillo-Facial Sciences, Section of Orthodontics, University Federico II, 80125 Naples, Italy; E-Mail: Alberto.Laino@unina.it * Author to whom correspondence should be addressed; E-Mail: Chiarella.Sforza@unimi.it.

Received: 1 October 2010 / Accepted: 19 October 2010 / Published: 9 November 2010 Abstract: We are currently investigating measurable esthetic characteristics in persons considered “attractive” by the media. Three-dimensional soft-tissue facial asymmetry was quantified in 380 attractive (148 males, 232 females) and 669 control (397 males, 272 females) healthy persons aged 4–30 years. The coordinates of 50 facial landmarks were collected by a computerized digitizer, and asymmetry computed. Soft-tissue facial asymmetries reduced as a function of age in all cases. Attractive children were more symmetric than control children, but the reverse was true for young adults. The effect of symmetry on attractiveness seems to change as a function of age.

Keywords: attractiveness; face; symmetry; three-dimensional

1. Introduction Asymmetry is a common finding in both the craniofacial hard tissues, and in the facial appearance, where the soft tissue cover (muscles, skin, adipose tissue) may partly mask the underlying imbalances [1–9]. Asymmetry is also found in the movement of facial mimic muscles: in healthy subjects, facial expressions, and in particular spontaneous smile, are larger on the left- than on the right-side of the face [10–12].

Symmetry 2010, 2 1926 Facial asymmetry is better appreciated using a three-dimensional approach that allows a direct measurement of the two facial halves [6,7,13,14], because the visual, qualitative assessment is often insufficient. For instance, skeletal asymmetries of less than 3% are not clinically discernible [5,15]. If the points of ear insertion cannot be easily identified, facial depth may be of difficult visual evaluation [16]. Indeed, in the face all three spatial components (right-left, cranio-caudal, anteriorposterior) can be asymmetric. In particular, the facial lower third can be very asymmetric in the anteroposterior plane [2,8], a finding neglected in the conventional two-dimensional photographic or radiographic views [1,5,17–19].

According to the current theories of evolutionary psychology, the esthetic assessment of adult faces depends on various combinations of averageness, symmetry, neoteny (babyness) and youthfulness, and sexual dimorphism [19–27]. Additionally, facial expression (happiness, excitement, arousal) and grooming (successful adaptation, status) concur to a global positive assessment [21].

Both natural and sexual selections seem to explain the various perceptions of attractiveness, with almost consistent ratings across sexes, ethnic groups and ages [13,20,24–26]. Recently, these investigations were extended also to children and adolescents [28–31]. Overall, the studies confirmed some of these theories: attractive children, female adolescents and adult women had faces with several characteristics of babyness: a large face with a relatively large forehead; relatively prominent cheekbones; reduced vertical development; full and prominent lips, and a more convex soft-tissue facial profile, than normal coetaneous persons [20,21,28–32]. In contrast, in post-pubertal adolescent boys and adult men, attractiveness seems to be positively influenced by facial markers of high testosterone levels (a signal of sexual dimorphism), with a relative increment of the facial lower third (more prominent chin, less prominent lips) [20,22,25,30,33].

In our laboratory, we are currently studying the three-dimensional facial characteristics of children, adolescents, adult males and females considered “attractive” by the general public [30–32]. Their facial soft tissues were measured with a non-invasive computerized instrument, several measurements obtained, and compared to those collected in healthy persons of the same sex, age and ethnicity, selected using criteria of dentofacial normality (Figure 1). The presence of measurable specific characteristics was assessed. If esthetically pleasing faces possess some kind of codified facial dimensions, angles and ratios, these measurements could be used by medical and dental practitioners for a better patient care [6,9,34]. Previous investigations performed on these attractive persons assessed the hypotheses of babyness/ youthfulness (found to explain a large part of facial attractiveness in children, adolescent girls, and adult women) and of sexual dimorphism (an effect found in adult women, in male adolescents, and in adult men) [30–32]. On no occasion, was data about their facial symmetry/ asymmetry assessed.

Symmetry 2010, 2 1927 Figure 1. Facial landmarks digitized on all subjects for subsequent morphometric calculations. Midline landmarks: tr, trichion; g, glabella; n, nasion; prn, pronasale;

c’, columella; sn, subnasale; ls, labiale superius; sto, stomion; li, labiale inferius;

sl, sublabiale; pg, pogonion; me, menton. Paired (right and left side) landmarks:

ex, exocanthion; en, endocanthion; os, orbitale superius; or, orbitale; ft, frontotemporale;

chk, cheek; zy, zygion; t, tragion; al, alare; ac, nasal alar crest; itn, inferior point of the nostril axis; stn, superior point of the nostril axis; cph, crista philtri; ch, cheilion; go, gonion; pra, preaurale; sa, superaurale; pa, postaurale; sba, subaurale.

1.1. Facial Symmetry and Attractiveness

Asymmetry can be divided into antisymmetry, directional and fluctuating asymmetry. In antisymmetry, either side of the body could be dominant (for instance, handedness). Directional asymmetry is consistently dominant on one side (for instant, heart position), while fluctuating asymmetry relates to traits that are on average symmetric in a population. Fluctuating asymmetry is considered to result from unbalances in growth and development of the various structures, with a reduced capacity of the organism to buffer environmental disturbances and genetic stressors [4,13,14,19,26,35–37]. From this point of view, the assessment of fluctuating asymmetry may provide useful information about the combined action of developmental stress and individual capacity to react.

An increased fluctuating asymmetry has been related to higher morbidity and mortality, reduced fecundity, inferior locomotory performance [13,35]. In contrast, a reduced fluctuating asymmetry has been associated with increased attractiveness, both in the face and in the body [13,19,21–24,27].

Symmetry 2010, 2 1928 Current explanations about the effect of facial symmetry on attractiveness can be summarized into three main aspects: symmetry is an important signal of good health and developmental stability; during visual inspection, symmetric faces are easier to scan and understand; symmetric faces are nearer to the average, prototype face [19,21–24,27]. Persons with symmetric faces and bodies suggest to the observer that they possess good genes, a good general health, and are more resistant to diseases and parasites. Symmetric faces become “honest” markers of genotype and phenotype quality: Symmetry reflects the individual ability to maintain a stable development notwithstanding the environmental stress, thus being the result of natural selection [4,13,19,21,23,24,26,36,38].

Despite these theories, not all investigators concord about a strict relationships between facial symmetry and attractiveness from one side, and facial asymmetry and disease (or altered development) from the other side [1,12,18,21,27,36,38]. For instance, Peck et al. [5] found that men and women considered attractive by the general public (beauty competition winners, professional models) had asymmetries in one or more craniofacial skeletal dimensions. Zaidel and Hessamian [36] found that both full and hemi-faces (only right or left side of the face) were rated similarly in terms of attractiveness. Shaner et al. [14] did not find an increase in soft-tissue facial asymmetry in syndrome affected individuals as compared to normal persons.

In our previous investigations, among the various analyzed parameters, the effect of facial symmetry on attractiveness was not considered. In the current study, we assessed the effect of facial symmetry/asymmetry on attractiveness by analyzing a wide group of attractive persons of both sexes ranging from four to 30 years of age, as well as a group of normal persons of the same age, sex and ethnic group. Their fluctuating soft-tissue facial asymmetry was quantitatively obtained from the three-dimensional coordinates of selected soft-tissue facial landmarks [14]. In a first analysis, linear distances and landmark coordinates were considered using a method previously developed in our laboratory, and that had been used to assess sex- and age- related variations in healthy people, as well as the effect of pathology and relevant treatment [3,8,39]. The method has been constructed considering the object symmetry of the human face [37]; it allows to separate the effect of selected landmarks to the total facial asymmetry, as recently underlined [40], and it has proved to supply clinically relevant information [8,39].

Attractive persons were selected by casting agencies or by judges of beauty competitions, without any knowledge of the aims and scope of the current investigations (see details below). Similar protocols were followed by Peck et al. [5] and by Ing et al. [18] for two-dimensional hard- and softtissue craniofacial characteristics. This procedure contrasts with that followed in most studies about facial attractiveness, where the judgment was made on photographs (both original images, and composite or manipulated faces) of unselected persons [19,21–26,33,36,38].

1.2. Selection of Attractive Persons

–  –  –

several national beauty competitions, which took place in Italy between 2006 and 2008. They were those admitted to the semi-final and final stages of beauty competitions, and were measured just before the semi-final stage of the relevant competition [32].

2. Results and Discussion

2.1. Total, Midline and Lateral Facial Asymmetry In both sexes, attractive and control subjects significantly differed in several of the analyzed symmetry descriptors, which assessed separately the contribution of the midplane (DFSm) and lateral (DFSl) asymmetries to the total facial asymmetry (DFSt) (Table 1). In both sexes, the factor age (two-way factorial analysis of variance) was always significant (p 0.001), with a general trend of reduced asymmetry with growth and development (Figures 2–4). Similar patterns were obtained by both the lateral symmetry and the midline symmetry. Indeed, as suggested by Klingenberg et al. [37], the analysis of object symmetry (a structure symmetric in itself, because it is intersected by the midsagittal plane) should consider the variations of structural features in the median plane separately from those of the features located in the right and left sides.

–  –  –

According to Haraguchi et al. [17], the level of two-dimensional soft-tissue facial asymmetry was independent from age or sex of the subject. Similar results were reported by Rossi et al. [7] for threedimensional skeletal measurements. In contrast, in healthy subjects Ferrario et al. [3] reported that three-dimensional soft-tissue facial asymmetry decreased from adolescence to adult age, a finding well replicated in the current study for both control and attractive subjects (Figures 2–4). It appears that the level of asymmetry, and its distribution in the population, depends on both the analyzed structures (hard vs. soft tissues), and the used method (two- vs. three-dimensional assessment).

In control male subjects, lateral asymmetry was always larger than midplane symmetry, contributing between 71% (4–5 year-old boys and 15–17 year-old adolescents) and 91% (8–10 year-old boys) to the total facial asymmetry. In attractive boys and men, a different pattern was observed, with lateral asymmetry explaining only up to 68% (4–5 year-old boys) of total asymmetry.

Similar patterns of lateral/ midplane asymmetry contributions were observed in control (between 46 and 96%) and attractive (between 49 and 61%) females. For control subjects, these values were Symmetry 2010, 2 1930 somewhat lower than those previously reported by Ferrario et al. [3] for healthy adolescents and young adults.

–  –  –

-1 4

–  –  –

Percentage asymmetry was assessed to account for the different facial dimensions in the analyzed age groups and in the two sexes. In the youngest girls, percentage asymmetry was on average 20–25% of the nasion–facial barycenter distance, and it reduced to 15% in the subsequent age groups (Figure 4). In adolescent girls and in adult women, it remained lower than 12%, except in attractive women (“Miss”), with an average percentage asymmetry of about 15%. For control “old” adolescent girls and women, these values were very similar to those previously reported in literature [3].

Symmetry 2010, 2 1931

–  –  –

Similar values were found in boys: the average percentage asymmetry was between 20 and 25% in the youngest age group, with subsequent reductions of around 15%. Adolescent and adult males had average percentage asymmetry values very close to those found in females (around 12%); the largest value was found in the attractive men (“Mister”). Literature reports for adolescent boys aged 12 to 15 years (comparable with the current “young” adolescent boys) and for young adult men are in good accord with the current values [3].

Pages:   || 2 | 3 | 4 |

Similar works:

«Estimates of Medical Device Spending in the United States Roland “Guy” King, F.S.A., M.A.A.A. Gerald F. Donahoe1 Abstract Advances in medical technology have long been believed to be a major driver of health care costs, but surprisingly little is known about the aggregate value and prices of one of the major types of medical technology, medical devices and diagnostics. This data note analyzes spending on medical devices for 1989-2004. Prices for medical devices consistently grew more slowly...»

«REPROGRAMMING HUMAN BLOOD CELLS by Bin-Kuan Chou A dissertation submitted to Johns Hopkins University in conformity with the requirements for the degree of Doctor of Philosophy Baltimore, Maryland November 2013   Abstract Reprogramming differentiated somatic cells to developmentally more potent states opens up a new era in regenerative medicine and research. In particular, the generation of induced pluripotent stem cells (iPSCs) which are expandable and pluripotent offers unprecedented...»

«RECIPES FOOD FOR HEALTH AND SOUL Decrease your risk of heart disease, cancer and diabetes by the preparation of healthy “soul food” and other family favorites. The University of Nevada, Reno is an equal opportunity affirmative action employer and does not discriminate on the basis of race, color, religion, sex, age, creed, national origin, veteran status, physical or mental disability, and in accordance with University policy, sexual orientation, in any program or activity it operates. The...»

«Blindness to the Benefits of Ambiguity: The Neglect of Learning Opportunities Stefan T. Trautmann Tilburg University Richard J. Zeckhauser Harvard University October, 2010 Abstract: Financial, managerial, and medical decisions often involve alternatives whose possible outcomes have ill defined probabilities. In contrast to risky alternatives, i.e., those whose probabilities are known, these ambiguous alternatives offer the benefits of learning. In repeatchoice situations, such learning brings...»

«SAFETY MONITORING of MEDICINAL PRODUCTS Reporting system for the general public SAFETY MONITORING of MEDICINAL PRODUCTS Reporting system for the general public n WHO Library Cataloguing-in-Publication Data Safety monitoring of medical products: reporting system for the general public.1.Essential drugs – standards. 2.Drug monitoring. 3.Adverse drug reaction reporting systems. 4.Pharmacovigilance. 5.Drug utilization review – methods.6.Consumer participation. I.World Health Organization. ISBN...»

«Trä hier, In Deinen Träumen warst Du schon hier, komme wieder und lebe Deinen Traum! i|àtÄ@V{tÄxà@exáÉÜà ==== i|àtÄ@V{tÄxà@ `|ÜÇÉv~ tÅ `|ÄÄáàùààxÜ fxx `|ÄÄáàù Projektbeschreibung Das Vital-Chalet-Resort**** Mirnock Millstätter See mit Medical-Wellness-Center,liegt eingebettet in die Region Oberkärnten am Mirnock, welcher am Millstättersee fußt. Die Region Millstätter See zeichnet sich durch seine ganzjährige Attraktivität aus. Die wahrscheinlich meisten...»

«NITRATES, GROUNDWATER, AND ONSITE SEWAGE SYSTEMS IN INDIANA A Report to the Legislature A Joint Report by Indiana State Department of Health Indiana Department of Environmental Management December, 2008 Introduction This report has been prepared at the request of the Indiana State Legislature. The 2004 General Assembly adopted non-code Section HB1017, Section 7, which states that the Department of Environmental Management and the State Department of Health shall jointly prepare a report that...»

«Centre for Policy Studies University College Cork National University of Ireland Working Paper Series CPS WP: 13-011 DISPARITIES IN THE HEALTH OF IRISH REGIONS: FIRST ESTIMATES Martin Kenneally* Brenda Lynch** Centre for Policy Studies Centre for Policy Studies University College Cork University College Cork Cork, Ireland Cork, Ireland m.kenneally@ucc.ie brendalynch@ucc.ie Tel: (+353) 214-902-572 Tel: (+353) 214-902-636 Fax: (+353) 214-903-658 Fax: (+353) 214-902-636 This Paper constitutes...»

«Functional characterization of Pseudouridine synthase I and Y-box-binding protein 3 Inaugural-Dissertation to obtain the academic degree Doctor rerum naturalium (Dr. rer. nat.) submitted to the Department of Biology, Chemistry and Pharmacy of Freie Universität Berlin by Alexandra Iulia Vasile Submitted 19.11.2015 1st Reviewer: Dr. Markus Landthaler Berlin Institute for Medical Systems Biology (BIMSB) Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association D-13125 Berlin,...»

«METH O R A L H E A LT H A GUIDE FOR DENTAL PROFESSIONALS Meth and Oral Health A Guide for Dental Professionals Hazelden Center City, Minnesota 55012-0176 1-800-328-9000 1-651-213-4590 (fax) www.hazelden.org ©2007 by Hazelden Foundation All rights reserved. Published 2007 Printed in the United States of America Duplicating this guide is not permissible. The handouts on pages 15–16 and 17 may be duplicated for professional use, but may not be sold or repurposed for other uses without the...»

«THE LIVED EXPERIENCE OF YOUNGER WOMEN WITH CANCER OF THE VULVA: A PHENOMENOLOGICAL STUDY by HILARY JANE JEFFERIES A thesis submitted to The University of Birmingham For the degree of DOCTOR OF PHILOSOPHY School of Health Sciences The University of Birmingham September 2008 Abstract Cancer of the vulva is a comparatively rare cancer that requires radical surgery. Whilst the physical effects of the surgery can readily be described, little is known about the psychological, emotional and social...»

«Study on the environmental risks of medicinal products FINAL REPORT Executive Agency for Health and Consumers 12 December 2013 Document information Executive Agency for Health and Consumers CLIENT CONTRACT NUMBER REPORT TITLE Final Report NAME OF THE STUDY Study on the environmental risks of medicinal products PROJECT TEAM BIO Intelligence Service DATE 12 December 2013 AUTHORS Mr. Shailendra Mudgal, BIO Intelligence Service Ms. Arianna De Toni, BIO Intelligence Service Ms. Sarah Lockwood, BIO...»

<<  HOME   |    CONTACTS
2016 www.dissertation.xlibx.info - Dissertations, online materials

Materials of this site are available for review, all rights belong to their respective owners.
If you do not agree with the fact that your material is placed on this site, please, email us, we will within 1-2 business days delete him.