SILVANA REGINA PRADO PENTEADO DE CASTRO
USO DOS TRIÂNGULOS MASTOIDES PARA DETERMINAÇÃO DO
SEXO EM UMA AMOSTRA BRASILEIRA
USE OF MASTOID TRIANGLES FOR SEX DETERMINATION IN A
BRAZILIAN SAMPLE
Piracicaba
2020
SILVANA REGINA PRADO PENTEADO DE CASTRO
USO DOS TRIÂNGULOS MASTOIDES PARA DETERMINAÇÃO DO
SEXO EM UMA AMOSTRA BRASILEIRA
USE OF MASTOID TRIANGLES FOR SEX DETERMINATION IN A
BRAZILIAN SAMPLE
Dissertação apresentada à Faculdade de Odontologia de Piracicaba da Universidade Estadual de Campinas, como parte dos requisitos exigidos para a obtenção do Título de Mestra em Biologia Buco-Dental, área de Anatomia.
Dissertation presented to the Piracicaba Dental School of the University of Campinas in partial fulfillment of the requirements for the degree of Master in Buco-Dental Biology, in Anatomy area.
Orientador: Profº. Drº. Fausto Bérzin
ESTE EXEMPLAR CORRESPONDE À VERSÃO FINAL DA DISSERTAÇÃO DEFENDIDA PELA ALUNA SILVANA REGINA PRADO PENTEADO DE CASTRO, E ORIENTADA PELO PROFº. DRº FAUSTO BÉRZIN.
Piracicaba
2020
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES). Número do processo: 88882.434534/2019-01.
DEDICATÓRIA
Dedico este trabalho a Deus, pela proteção, pela força, e pela coragem durante essa caminhada.
AGRADECIMENTOS
O presente trabalho foi realizado com apoio da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) - Código de Financiamento 001.
A Deus, que iluminou o meu caminho, se fez presente em cada segundo da minha vida, e permitiu que esse sonho se tornasse realidade.
À Universidade Estadual de Campinas, na pessoa do Magnífico Reitor Prof. Dr. Marcelo Knobel, e à Faculdade de Odontologia de Piracicaba, na pessoa do Senhor Diretor, Prof. Dr. Francisco Haiter Neto.
Ao meu amor Luiz, que desde o início não mediu esforços para me ajudar, companheiro das madrugadas, dos finais de semanas em casa, por ter vivido comigo todos os detalhes desse trabalho, e sempre me incentivando a caminhar em busca dos meus sonhos e objetivos.
Aos meus pais Zélio e Irma (in memoriam), com todo meu amor e gratidão, por tudo que fizeram por mim ao longo da minha vida. Desejo poder ter sido merecedora do esforço dedicado por vocês em todos os aspectos, especialmente quanto à minha formação.
À Coordenadoria de Pós-Graduação, na pessoa da Coordenadora Profa. Dra. Karina Gonzales Silvério Ruiz e à equipe técnica composta por Ana Paula Carone, Érica A. Pinho Sinhoreti e Leandro Viganó.
Ao Programa de Pós-graduação em Biologia Buco-dental, na pessoa de Profa. Dra. Ana Paula de Souza.
Ao meu orientador Prof. Dr. Fausto Bérzin, exemplo de força e dedicação, por todo conhecimento, paciência e amizade construídos e compartilhados. Gratidão imensa por todo o apoio recebido.
Aos amigos que fiz e com o quais fortaleci laços, por todos os momentos juntos tornando cada dia ainda mais memorável.
À FOP-UNICAMP, que transformou a humilde aprendiz em pessoa com projetos e ambições para o futuro.
AGRADECIMENTO ESPECIAL
À Prof.ª Dra. Ana Claudia Rossi, mestre, amiga, que com muita paciência, amor, e dedicação, soube entender minhas limitações, e dificuldades. Obrigada pelo incentivo, e por me ajudar muito com sua competência e seriedade. Seus ensinamentos estarão presentes por toda a minha vida.
Agradeço imensamente por fazer parte da minha conquista. Deus abençoe!
“Que os nossos esforços desafiem as impossibilidades. Lembrai-vos que as grandes proezas da história foram conquistas daquilo que parecia impossível”
RESUMO
A identificação humana envolvendo mutilação, decomposição avançada e materiais esqueletizados é um desafio para os profissionais da medicina e odontologia legal. A validação de metodologias e técnicas antropológicas confiáveis nas mais diversas populações é essencial para os serviços de identificação humana. Parâmetros métricos e morfológicos para determinar o sexo na população brasileira têm sido cada vez mais relevantes na medicina forense e odontologia. Este estudo teve como objetivo uma análise morfométrica da região mastoide em uma população brasileira para determinar o sexo, utilizando padrões especificamente estabelecidos para brasileiros. Este estudo incluiu 80 crânios humanos (34 femininos e 46 masculinos) obtidos da coleção osteológica documentada do Biobanco (ossos, dentes e cadáveres humanos) do departamento de biociências da Faculdade de Odontologia de Piracicaba (UNICAMP). Foram excluídos crânios envolvendo fraturas ou traumas extensos na região da mastoide e na base do crânio. O protocolo deste estudo consiste em nove medidas lineares dos triângulos mastoides direito e esquerdo e do triângulo bimastoide. As regiões mastoide direita e esquerda foram determinadas com base em três pontos cranianos: astério, pório e mastoide. O triângulo bimastoide foi determinado com base em três pontos: opístio e as mastoides direita e esquerda. As medidas foram realizadas por dois pesquisadores previamente treinados após uma calibração intra e interexaminadores. Essas dimensões foram usadas para calcular as áreas do triângulo usando a fórmula de Heron. O software GraphPad Prism 5.01 (GraphPad, San Diego, EUA) foi utilizado para análises estatísticas (Shapiro-Wilk, teste T de Student e teste U de Mann Whitney). A curva ROC foi usada para estimar a precisão das medidas para determinar o sexo, representado visualmente pelo cálculo da área sob a curva ROC. A correlação linear for realizada seguida da análise de regressão. Para todas as análises foi considerado um valor de p menor que 5% (p<0,05). Diferenças significativas no comprimento linear dos pontos mastoides e na área do triângulo mastoide, ambos do lado direito, foram observadas entre os sexos, sendo os valores médios mais altos para homens do que para mulheres. No triângulo opístio-bimastoide todas as análises apresentaram diferenças significativas. Com base em nossos resultados, os parâmetros morfométricos avaliados podem ser utilizados para determinar o sexo na amostra brasileira estudada.
ABSTRACT
Human identification involving mutilation, advanced decomposition, and skeletonized materials is a challenge for professionals in forensic medicine and dentistry. Validating reliable anthropological methodologies and techniques in the most diverse populations is essential for human identification services. Metric and morphological parameters for determining the sex in the Brazilian population have been increasingly relevant in forensic medicine and dentistry. This study was aimed at a morphometric analysis of the mastoid region in a Brazilian population to determine the sex, using standards specifically established for Brazilians. This study included 80 human skulls (34 female and 46 male) obtained from the documented osteological collection of the biobank (human bones, teeth and corpses) of the department of biosciences at Piracicaba dental school (UNICAMP). Skulls involving extensive fractures or trauma in the region of the mastoid and at the base of the skull were excluded. This study protocol consists of nine linear measurements of the right and left mastoid triangles and the bimastoid triangle. The right and left mastoid regions were determined based on three cranial points: asterion, porion and mastoid. The bimastoid triangle was determined based on three points: opisthion and the right and left mastoids. The measurements were taken by two previously trained researchers after an intra- and inter-examiner calibration. These dimensions were used to calculate the triangle areas using the Heron’s formula. GraphPad Prism 5.01 (GraphPad, San Diego, EUA) software was used for statistical analyses (Shapiro-Wilk, Student T test, and Mann Whitney U test).The ROC curve was used to estimate the accuracy of the measures to determine the sex, which is represented visually by calculating the area under the ROC curve. The linear correlation was performed followed by regression analysis. For all analyses, a value of p less than 5% (p <0.05) was considered significant. Significant differences in the linear length of the mastoid points and in the area of the mastoid triangle, both on the right side, were observed between genders, with mean values being higher for men than for women. In the opisthion-bimastoid triangle, all analyses showed significant differences. Based on our results, the morphometric parameters assessed can be used to determine sex in the studied Brazilian sample.
Sumário
1 INTRODUÇÃO ... 11
2 ARTIGO: Application of mastoid and opisthion-bimastoid triangles for sex determination in a Brazilian sample ... 14
3 CONCLUSÃO ... 31
REFERÊNCIAS ... 32
ANEXO 1 – Comprovante de Submissão ... 34
ANEXO 2 – Certificado de Aprovação no Comitê de Ética em Pesquisa ... 35
1 INTRODUÇÃO
O processo de identificação humana nos casos de cadáveres mutilados, em estado avançado de decomposição ou material esqueletizado, é um desafio para a Medicina e Odontologia Legal. Nesse sentido, o foco principal para a identificação é a reconstrução do perfil biológico por meio da estimativa de idade e estatura, e a determinação do sexo e da ancestralidade (Kanchan et al. 2013).
Um dos principais indicadores biológicos de identidade é o sexo de um indivíduo, mostrando dessa forma, a importância do dimorfismo sexual na identificação do esqueleto humano remanescente (Krishan et al. 2016).
Em um cadáver esqueletizado, o sexo pode ser determinado através das características morfológicas da pelve com alto nível de confiabilidade (Musilová et al. 2016). Porém, quando os ossos do quadril estão fragmentados ou não há presença da pélvis, a estimativa é realizada usando o crânio que fornece até 92% de confiabilidade (Bhayya et al. 2018; Colmenares et al. 2019).
O dimorfismo sexual no crânio humano e sua importância em situações médico-legais estão bem definidas (Deepali, Jasuja, Nath, 2013; Fatah et al. 2014). A craniometria sistematizada e universal possibilita comparar outros estudos realizados em diferentes populações, sendo útil para a obtenção dos diversos valores métricos de crânios humanos para finalidade científica (Krishan et al. 2016).
A capacidade de determinar o sexo utilizando o crânio reivindicada por diversos pesquisadores mostra uma variação considerável. Paiva e Segre (2003) avaliaram a determinação do sexo utilizando os valores obtidos da medida da área formada pela projeção xerográfica de três pontos craniométricos relacionados ao processo mastoide: os pontos pório, astério, e mastoide, os crânios masculinos e femininos puderam ser discriminados com 95% de confiança. A técnica foi originada por sua simplicidade e alta precisão.
Madadin et al. (2015) utilizaram 206 tomografias computadorizadas (TC) do crânio para avaliar a validade do triângulo mastoide na identificação do sexo em uma população saudita, e o resultado variou de 71,4% a 60,7%. Ressaltaram que a precisão pode ser maior se as medidas de TC do crânio forem comparadas com as avaliações morfométricas diretas do crânio.
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Singh et al. (2015) basearam o estudo em autópsia de 100 indivíduos e analisaram o triângulo mastoide para determinar o sexo em uma população da Índia. Realizaram a mensuração dos pontos: pório (ponto lateral mais alto do conduto auditivo externo), mastoide (ponto mais baixo do processo mastoide, e o astério (ponto de encontro da lambdoide occipitomastoide, e suturas parietomastoides). Os autores concluíram que a área do triângulo mastoide poderia ser usada para determinar o sexo em caso de restos fragmentados do crânio. No entanto, as outras medidas não são um bom indicador quando usadas individualmente.
Jung e Woo (2016) analisaram 200 crânios com o objetivo de subdividir o dimorfismo da mastoide em diferenças de tamanho e forma, e examinar se a forma da região mastoide pode ser um fator independente e confiável para estimar o sexo em americanos brancos modernos usando a morfometria geométrica. Os autores concluíram que o tamanho da mastoide apresentou uma acurácia de 87,3%, para classificar cada sexo, e a forma (12,7%) de acurácia. No entanto, essa diferença significativa não pode simplesmente afirmar que a região mastoide não pode ser um indicador independente e confiável do dimorfismo sexual em americanos brancos modernos.
Kramer et al. (2018) avaliaram 60 imagens de microtomografias (Micro-CT) de crânios secos para estimar o sexo em brasileiros através de variáveis do processo mastoide utilizando dois métodos diferentes: imagens analisadas pelo software myVGL 2.2 e três medidas lineares utilizando paquímetro do software. Os pesquisadores concluíram que a análise do processo mastoide apresentou bom dimorfismo sexual na população brasileira em crânios fragmentados, porém, em crânio completo outras metodologias são recomendadas por apresentar maior precisão.
Ibrahim et al. (2018) estudaram 388 exames de TC do crânio humano para desenvolver uma nova equação para a estimação do sexo a partir do triângulo mastoide na população da Malásia. Os parâmetros utilizados compreendiam os três lados do triângulo da mastoide, seu perímetro e a área em ambos os lados. Os autores relatam que a equação baseada no perímetro do triângulo da mastoide foi desenvolvida com acurácia de 84,4% e pode ser usada para avaliar o dimorfismo sexual em crânios fragmentados na Malásia, porém, com a região mastoide intacta.
Sinhorini et al. (2019), analisaram 100 crânios humanos brasileiros com o objetivo de validar e avaliar a eficácia de quatro métodos morfométricos para estimativa do sexo utilizando 15 medidas lineares para estimar cinco triângulos cranianos: triângulos
mastoides direito e esquerdo, triângulo bimastoide, triângulo facial e o triângulo occipital, e os achados nesse estudo mostrou que as porcentagens de acurácia média foram maiores nas análises multivariadas, e os quatro métodos morfométricos utilizados são bons preditores para estimativa sexual na população brasileira. A amostra foi considerada relativamente pequena, e os autores sugerem que mais estudos sejam realizados a fim de validar os resultados encontrados.
A hipótese deste estudo é que os triângulos mastoides e opístio-bimastoide podem ser utilizados para determinar o sexo na população brasileira. O objetivo desse estudo foi aplicar e avaliar a análise morfométrica do triângulo mastoide e do triângulo opístio-bimastoide para determinar o sexo em uma amostra da população brasileira, e auxiliar o âmbito forense em aplicações periciais na questão da determinação do sexo com padrões estabelecidos especificamente para brasileiros.
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2
ARTIGO:Application of mastoid and opisthion-bimastoid triangles for
sex determination in a Brazilian sample.
Authors:
Silvana Regina Prado Penteado de Castro1, Juliana Hadad1, Alexandre Rodrigues Freire1, Olavo Barbosa de Oliveira Neto2, Felippe Bevilacqua Prado1, Ana Cláudia Rossi1, Fausto Bérzin1.
1Piracicaba Dental School, Biosciences Department, University of Campinas,
Piracicaba, SP, Brazil.
2Department of Anatomy, Biosciences Center (CB), Federal University of
Pernambuco (UFPE), Recife, PE, Brazil.
*Correspondence to:
Silvana Regina Prado Penteado de Castro
Department of Biosciences, Anatomy Division, Piracicaba Dental School, University of Campinas.
Avenida Limeira 901- Areião, Piracicaba, São Paulo, Brazil. CEP13414-018. E-mail: silcastro1709@gmail.com
*O presente artigo foi submetido para apreciação no periódico internacional “Australian Journal of Forensic Sciences”.
ABSTRACT
The aim of this study was used the dimensions on the mastoid region to determine whether they could potentially be useful for determination of the sex in a Brazilian sample, the emphasis being on the triangular area technique. The sample consisted of 80 human skulls of which 34 were females and 46 males, with age range of 18 to 60 years. The skulls were selected from individual with death certificates. The morphometric analyzes for determining sex and applying the mastoid triangle method. Linear measurements were used to estimate three cranial triangles: the right and left mastoid triangles and the opisthion-bimastoid triangle. The Shapiro-Wilk normality test was performed followed by the unpaired Student's t test or the Mann-Whitney U test, depending on the distribution of data verified in the normality test. Different sides of individuals of the same sex were compared and the same side of individuals of different sexes. The ROC curve was used to estimate the accuracy of the measures to determine the sex, which is represented visually by calculating the Area under the ROC Curve. The linear correlation was performed followed by regression analysis. For all analyzes, a value of p less than 5% (p <0.05) was considered significant. The confidence level for this survey was set at 95%. The morphometric parameters related to the mastoid region are sexually dimorphic and the regression analysis showed the opisthion-bimastoid triangle is a predictor parameter to determine sex in the studied Brazilian sample.
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INTRODUCTION
One of the main biological indicators of human identification is the sex of an individual, showing the importance of sexual dimorphism in the identification of the remaining human skeleton (Krishan et al., 2016).
In a human skeleton, sex can be determined through the morphological characteristics of the pelvis with a high level of reliability (Musilová et al., 2016). However, when the hip bones are fragmented or there is no pelvis, the estimate is made using the skull that provides up to 92% reliability (Bhayya et al., 2018; Colmenares et al., 2019).
The sexual dimorphism in the human skull and its importance in medico-legal situations are well defined (Jain et al., 2013; Fatah et al., 2014). Systematic and universal craniometry makes it possible to compare other studies carried out in different populations, being useful for obtaining the various metric values of human skulls for scientific purposes (Krishan et al., 2016).
The compact structure and the anatomical position of the mastoid region of the skull make it highly resistant to any physical damage and thus it may remain intact in otherwise damaged and fragmented skulls. This explains the usefulness of the mastoid region in sex determination of the skull when other morphological and metric methods cannot be applied for sex determination of the skull (Madadin et al., 2015).
Singh et al. (2015) based the study on an autopsy of 100 individuals and analyzed the mastoid triangle to determine sex in a population in India. The points were measured: porion (highest lateral point of the external auditive canal), mastoid (lowest point of the mastoid process, and asterion (meeting point of the occipitomastoid lambdoid, and parietomastoid sutures) .The authors concluded that the area of the mastoid triangle could be used to determine sex in case of fragmented skull remains, however the other measures are not a good indicator when used individually. Jung and Woo (2016) analyzed 200 skulls in order to subdivide the mastoid dimorphism into differences in size and shape, and to examine whether the shape of the mastoid region can be an independent and reliable factor for estimating sex in modern white Americans using geometric morphometry. The authors concluded that the size of the mastoid presented an accuracy
of 87.3%, to classify each sex, and the shape (12.7%) of accuracy. However, this significant difference cannot simply state that the mastoid region cannot be an independent and reliable indicator of sexual dimorphism in modern white Americans.
Sinhorini et al. (2019) analyzed 100 Brazilian human skulls in order to validate and evaluate the effectiveness of four morphometric methods for sex estimation using 15 linear measures to estimate five cranial triangles: right and left mastoid triangles, bimastoid triangle, facial triangle and the occipital triangle, and the findings in the study showed that the percentages of average accuracy were higher in multivariate analyzes, and the four morphometric methods used are good predictors for sexual estimation in the Brazilian population. The sample was considered relatively small, and the authors suggest that further studies be carried out in order to validate the results found.
In the present study, considering the importance of the investigate the standardized index for sex determination in Brazilian population and the highlighted benefits of forensic measurements on the mastoid process, we used the dimensions on the mastoid region to determine whether they could potentially be useful for determination of the sex in a Brazilian sample, the emphasis being on the triangular area technique.
MATERIAL AND METHODS
This study was approved by the Ethics Committee of the Piracicaba Dental School, University of Campinas (FOP-UNICAMP), protocol number 19080019.3.0000.5418.
Sample
The sample consisted of 80 human skulls, chosen randomly from the set of bones from the Biobank “Human Bones, Teeth and Corpses” of the Piracicaba Dental School of University of Campinas (FOP/UNICAMP), of which 34 were females and 46 males, with age range of 18 to 60 years. All individuals in the collection were identified by death certificates.
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Skulls without fractures, trauma, pathological or surgical changes or anatomical variations in the region of interest in this study were included. Skulls with any damage or any type of anatomical variation were excluded.
Protocol of measurements
The measurements were performed by two researchers after a previous calibration among the examiners in a sample of 20 skulls. The examiners were blinded to the sex of the bones evaluated. After a period of one month, 20% of the sample was evaluated again by each of the researchers, to verify the intra- and inter-examiner reliability.
The protocol was phased in nine linear measurements by convention in this study. To standardize the measures, the median sagittal plane and the Frankfurt plane were used as a reference. For metric analyzes, a digital caliper (King Tools) was used (mm).
The morphometric analyzes for determining sex and applying the mastoid triangle method were based on the study by Sinhorini et al. (2019). Linear measurements were used to estimate three skull triangles: the right and left mastoid triangles and the opisthion-bimastoid triangle.
The right and left mastoid processes were estimated based on three cranial points: asterion (ast), porion (po) and mastoidale (ma) and three linear distances between the points: asterion-porion (side 1), asterion-mastoidale (side 2) and porion-mastoidale (side 3) (Figure 1).
Figure 1. The mastoidale triangle (left side), lateral view of the skull. asterion (ast), porion (po) and mastoidale (ma).
The bimastoid triangle was based on three reference points: the opisthion (o) and the left and right mastoidales (ma), three linear distances between the points: the opisthion (o) and left mastoidale (ma), the opisthion (o) and right mastoidale (ma), and the right and left mastoidales (ma).
Figure 2. The opisthion-bimastoid triangle, inferior view of the skull. opisthion (o) and mastoid (ma).
Statistical analysis
Initially, calculations of the perimeter and the area of the triangles were performed. The perimeters of the mastoid and opisthion-bimastoid triangles were calculated using the following model:
- Mastoid triangle perimeter = As-Po + As-Ma + Po-Ma
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The areas of the mastoid and opisthion-bimastoid triangles were calculated using the Heron’s formula (Kemkes and Göbel, 2006) and expressed in square millimeters (mm2), using the following model:
- Mastoid triangle area =
√((𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟/2) 𝑥 (𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟/2 – 𝐴𝑠 − 𝑃𝑜) 𝑥 (𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟/2 – 𝐴𝑠 − 𝑀𝑎 (𝐿)) 𝑥 (𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟/2 – 𝑃𝑜 − 𝑀𝑎))
- Opisthion-bimastoid triangle area=
√((𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟/2) 𝑥 (𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟/2 – 𝑂𝑝 − 𝑀𝑎 (𝑅)) 𝑥 (𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟/2 – 𝑂𝑝 − 𝑀𝑎 (𝐿)) 𝑥 (𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟/2 – 𝑀𝑎 − 𝑀𝑎))
The intraclass correlation coefficient (CCI) was calculated to determine the level of agreement between the evaluators. The Shapiro-Wilk normality test was performed followed by the unpaired Student's t test or the Mann-Whitney U test, depending on the distribution of data verified in the normality test. Different sides of individuals of the same sex were compared and the same side of individuals of different sexes.
The Receiver Operating Characteristic curve (ROC curve) was used to estimate the accuracy of the measures to estimate sex, which is represented visually by calculating the Area under the ROC Curve (AUC), where the greater the AUC, the greater is the potential of the variable in estimating sex.
The linear correlation was performed followed by regression analysis to correlate the variables of the mastoid triangles and the opisthion-bimastoid triangle to sex determination.
For all analyzes, a value of p less than 5% (p <0.05) was considered significant. The confidence level for this survey was set at 95%. The analyzes were performed using the GraphPad Prism 5.01 software (GraphPad, San Diego, USA).
RESULTS
Table 1 shows the comparison between the measures of the Mastoid Triangle considering different sides of individuals of the same sex. All analyzes showed no significant difference.
Table 1: Comparison between measures of the Mastoid Triangle considering different sides of individuals of the same sex. As-Po = Asterion-Porion distance; As-Ma = Asterion-Mastoid distance; Po-Ma = Asterion-Porion-Mastoid distance.
Male (N=46) Female (N=34)
As-Po As-Ma Po-Ma Perimeter Area As-Po As-Ma Po-Ma Perimeter Area
Right side Average (+/- Standard deviation) 46.25 (+/-5.785) 51.58 (+/-5.818) 29.06 (+/-2.862) 126.9 (+/-11.72) 661.0 (+/-111.9) 45.23 (+/-4.675) 47.72 (+/-9.330) 27.40 (+/-2.310) 120.3 (+/-12.89) 609.5 (+/-95.59) Left side Average (+/- Standard deviation) 46.12 (+/-4.829) 50.97 (+/-6.191) 29.02 (+/-3.569) 126.1 (+/-11.18) 655.5 (+/-105.0) 44.83 (+/-3.733) 49.00 (+/-4.882) 27.95 (+/-2.823) 121.8 (+/-9.524) 616.7 (+/-89.75) p value 0.4828 0.7931 0.9493 0.7663 0.5197 0.7017 0.7769 0.3850 0.6009 0.7487
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Figure 3 shows the comparison between the measures of the Mastoid Triangle considering the same side of individuals of different sexes. For the right side, the Po-Ma measurement showed a significant difference (p <0.05) between the sexes (a). Both, the perimeter and the area of the right mastoid triangle showed a significant difference (p <0.05) between the sexes (b).
Figure 3. Comparison between measures of the Mastoid Triangle considering the same side of individuals of different sexes. * = indicates significant difference (p <0.05). As-Po = Asterion-As-Porion distance; As-Ma = Asterion-Mastoid distance; As-Po-Ma = As- Porion-Mastoid distance; [M] = male; [F] = female; (R) = right side; (L) = left side.
Figure 4 shows the comparison between the measures of Opisthion-bimastoid triangle considering the same side of individuals of different sexes. All analyzes showed a significant difference. For the right side, the Op-Ma measurement showed a significant difference (p <0.05) between the sexes. For the left side, the Op-Ma measurement showed a significant difference (p <0.05) between the sexes. The Ma-Ma measure showed a significant difference (p <0.05) between the sexes. Both the perimeter and the area showed a significant difference (p <0.05) between the sexes.
Figure 4. Comparison between measures of the Opisthion-bimastoid triangle considering the same side of individuals of different sexes. * = indicates significant difference (p <0.05). Op-Ma = Opisthion-Mastoid distance; Ma-Ma = Mastoid-Mastoid distance (bimastoid); [M] = male sex; [F] = female sex; (R) = right side; (L) = left side.
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Table 2 shows ROC curve to the measures of the Mastoid Triangle. The higher the AUC, the greater the potential of the variable in determining sex.
Table 2. Area under the ROC Curve (AUC) for Mastoid Triangle measurements
* = indicates significant difference; CI = confidence interval; As-Po = Asterion-Porion distance; As-Ma = Asterion-Mastoid distance; Po-Ma = Porion-Mastoid distance.
Right side Left side
Measurement AUC CI p value AUC CI p value
As-Po 0.5671 0.4393 – 0.6949 0.3069 0.5764 0.4492 – 0.7036 0.2449
As-Ma 0.6279 0.5020 - 0.7537 0.05165 0.5818 0.4560 – 0.7077 0.2129
Po-Ma 0.6841 0.5674 - 0.8009 0.005083* 0.5793 0.4540 – 0.7045 0.2275
Perimeter 0.6317 0.5078 - 0.7557 0.04503* 0.5815 0.4554 – 0.7076 0.2147
Figure 5. Area under the ROC Curve (AUC) for measurements of the Opisthion-bimastoid triangle. *= indicates significant difference; CI = confidence interval; Op-Ma = Opisthion-mastoid distance; Ma-Ma = Mastoid-Mastoid distance (bimastoid); (R) = right side; (L) = left side.
The higher the AUC, the greater the potential of the variable in determining the sex. The figures 5 and 6 show the AUC for the Opisthion-bimastoid triangle with a high potential to determine the sex.
Figure 6. Area under the ROC Curve (AUC) for measurements of the Opisthion-bimastoid triangle. * = indicates significant difference; CI = confidence interval.
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Table 3. Regression analysis for Mastoid Triangle measurements.
Right side Left side
As-Po As-Ma Po-Ma Perimeter Area As-Po As-Ma Po-Ma Perimeter Area
R -0.1150 -0.2190 -0.3154 -0.2256 -0.2319 -0.1309 -0.1402 -0.1358 -0.1396 -0.1358 R2 0.009193 0.06231 0.08945 0.06709 0.05627 0.02114 0.02945 0.02580 0.04070 0.03706 CI -0.3324 to 0.1140 -0.4241 to 0.007407 -0.5054 to -0.09618 -0.4297 to 0.0004992 -0.4363 to -0.004629 -0.3466 to 0.09809 -0.3550 to 0.08869 -0.3511 to 0.09312 -0.3545 to 0.08925 -0.3511 to 0.09312 p value 0.3098 0.0510 0.0044* 0.0442* 0.0398* 0.2473 0.2150 0.2298 0.2168 0.2298
* = indicates significant difference; CI = confidence interval; As-Po = Asterion-Porion distance; As-Ma = Asterion-Mastoid distance; Po-Ma = Porion-Mastoid distance.
Table 4. Regression analysis for the Opisthion-bimastoid triangle measurements.
Op-Ma (R) Op-Ma (L) Ma-Ma Perimeter Area
R -0.3679 -0.3597 -0.3679 -0.4084 -0.2690 R2 0.09274 0.1403 0.1353 0.1826 0.07993 CI -0.5484 to -0.1547 -0.5417 to -0.1455 -0.5484 to -0.1547 -0.5809 to -0.2009 -0.4679 to -0.04423 P value 0.0008* 0.0010* 0.0008* 0.0002* 0.0165*
* = indicates significant difference; CI = confidence interval; Op-Ma (R) = mastoid distance on the right side; Op-Ma (L) = Opisthion-mastoid distance on the left side; Ma-Ma = Mastoid-Mastoid Distance (BiOpisthion-mastoid).
To explore the potential accuracy of possible measurements for application to skulls, the regression analysis was performed (Tables 3 and 4). The Mastoid triangle (Table 3) shows a low prediction to determine the sex. The Opisthion-bimastoid triangle.
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DISCUSSION
There is a deficiency of metric and morphological parameters pre-established for the Brazilian population, and the estimation of sex for forensic purposes through anatomical characteristics becomes very important (Kramer et al., 2018). In this sense, validating reliable methodologies in the most diverse populations in the world are essential to improve and qualify anthropological techniques in human identification services (Sinhorini et al. 2019).
Our study revelated that the measurements of areas and perimeters of the right mastoid and opisthion-bimastoid triangles showed significant differences between genders. These differences were found in the length of the Porion-Mastoid distance and the area of the mastoid triangle, both on the right side, as these variables showed higher mean values for male than female sex. Yilmaz et al. (2015) verified the mastoid region exhibits a degree of sexual dimorphism in adult humans. The difference in size could be explained by different growth periods of men and women, in addition to the greater development in men is explained by the more powerful action of the muscles that are inserted there: sternocleidomastoid, splenic head and long head. Our results also show us the predilection for the right side, thus observing laterality as the body's morphological principle.
ROC analysis in the present study showed the sexing potential of opisthion-bimastoid triangle is high. And the sexing potential of mastoid triangle is low. Our observations that are suggestive of a lower accuracy level of mastoid triangle dimensions are similar to those reported by Kemkes and Göbel (2006).
Paiva and Segre (2003) were pioneers in the evaluation of the mastoid triangle to identify sex, and since the publication of this Brazilian study, researchers have tried to assess the utility of the mastoid triangle in determining sex in small populations in some countries. The mastoid process is more accurate in the discrimination of sex and is considered the best individual parameter in sexual dimorphism (Kanchan, Gupta, Krishan, 2013; Sinhorini et al., 2019).
The morphometric parameters related to the mastoid region are sexually dimorphic and the regression analysis showed the opisthion-bimastoid triangle is a predictor parameter to determine sex in the studied Brazilian sample.
ACKNOWLEDGMENT
We are grateful to the Coordination for the Improvement of Higher Education Personnel (CAPES).
REFERENCES
1. Bhayya H; Tejasvi ML; Jayalakshmi B; Reddy M. Craniometric assessment of gender using mastoid process. J Indian Acad Oral Med Rad. 2018 [cited 2019 Jun 21]; 30: 52-7. Available from: http://www.jiaomr.in/text.asp?2018/30/1/52/230883
2. Fatah EEA, Shirley NR, Jantz RL, Mahfouz MR. Improving Sex Estimation from Crania Using a Novel Three-dimensional Quantitative Method. J Forensic Sci. 2014; 59(3): 590-600. Available from: https://doi.org/10.1111/1556-4029.12379
3. González-Colmenares G, Sanabria Medina C, Rojas-Sánchez MP, León K, Malpud A. Sex estimation from skull base radiographs in a contemporary Colombian population. J Forensic Leg Med. 2019; 62:77‐81. doi: 10.1016/j.jflm.2019.01.006 4. Jain D, Jasuja OP, Nath S. Sex determination of human crania using Mastoid triangle and Opisthion-Bimastoid triangle. J Forensic Leg Med. 2013;20(4):255‐259. doi:10.1016/j.jflm.2012.09.020
5. Jung H, Woo EJ. Evaluation of Mastoid Process as Sex Indicator in Modern White Americans using Geometric Morphometrics. J Forensic Sci. 2016;61(4):1029‐1033. doi:10.1111/1556-4029.13079
6. Kanchan T, Gupta A, Krishan K. Estimation of sex from mastoid triangle – A craniometric analysis. J Forensic and Legal Med. 2013; 20(7): 855-60. Available from: https://doi.org/10.1016/j.jflm.2013.06.016
7. Kemkes A, Göbel T. Metric assessment of the "mastoid triangle" for sex determination: a validation study. J Forensic Sci. 2006;51(5):985‐989. doi:10.1111/j.1556-4029.2006. 00232.x
8. Kramer NA et al. Sex estimation from the mastoid process using Micro-CT among Brazilians: Discriminant analysis and ROC curve analysis. J Forensic Rad Imag. 2018; 14: 1-7. Available from: https://doi.org/10.1016/j.jofri.2018.05.003
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9. Krishan K, Chatterjee PM, Kanchan T, Kaur S, Baryah N, Singh RK. A review of sex estimation techniques during examination of skeletal remains in forensic anthropology casework. Forensic Sci Int. 2016; 261:165. e1‐165.e1658. doi: 10.1016/j.forsciint.2016.02.007
10. Madadin M, Menezes RG, Al Dhafeeri O, et al. Evaluation of the mastoid triangle for determining sexual dimorphism: A Saudi population-based study. Forensic Sci Int. 2015; 254:244. e1‐244.e2444. doi: 10.1016/j.forsciint.2015.06.019
11. Musilová B, Dupej J, Velemínská J, Chaumoitre K, Bruzek J. Exocranial surfaces for sex assessment of the human cranium. Forensic Sci Int. 2016; 269:70‐77. doi: 10.1016/j.forsciint.2016.11.006
12. Paiva LAS, Segre M. Sexing the human skull through the mastoid process. Rev Hosp Clin 2003 [On-line] [cited 2019 Jun 22]; 58(1). Available from: http://dx.doi.org/10.1590/S0041-87812003000100004
13. Singh PK, Menezes RG, Shetty BSK, Rastogi P, Kanchan T, Rao J et al. Morphometric sex determination from mastoid triangle in South Indian population. Health Renaissance. 2015;13(2): 105-113.
14. Sinhorini PA, Costa IAP, Lopez-Capp TT, Biazevic MGH, de Paiva LAS. Comparative analysis of four morphometric methods for sex estimation: A study conducted on human skulls. Leg Med (Tokyo). 2019; 39:29‐34. doi: 10.1016/j.legalmed.2019.06.001
15. Yilmaz MT, Yüzbasioglu N, Cicekcibasi AE, Seker M, Sakarya ME. The evaluation of morphometry of the mastoid process using multidetector computed tomography in a living population. J Craniofac Surg. 2015;26(1):259‐263. doi:10.1097/SCS.0000000000001216
3 CONCLUSÃO
Nosso estudo mostrou diferenças significantes entre os sexos com variáveis mais altas para homens do que para mulheres nas medidas de áreas e perímetros dos triângulos mastoide e opístio-bimastoide.
No triângulo mastoide as diferenças foram constatadas no comprimento da distância entre os pontos pório-mastoide e da área do triângulo mastoide, ambos do lado direito. É suficientemente preciso para determinar o sexo quando utilizado individualmente.
No triângulo opístio-bimastoide todas as análises apresentaram diferenças significantes. A análise de regressão mostrou que o triângulo opístio-bimastoide é um parâmetro preditor melhor quando comparado com o triângulo mastoide para determinar o sexo na amostra brasileira estudada.
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REFERÊNCIAS1
1. Kanchan T, Gupta A, Krishan K. Estimation of sex from mastoid triangle – A craniometric analysis. J Forensic and Legal Med. 2013; 20(7): 855-60. Available from: https://doi.org/10.1016/j.jflm.2013.06.016
2. Krishan K et al. A review of sex estimation techniques during examination of skeletal remains in forensic anthropology casework. J Forensic Sci Int. 2016; 261: 165.e1-165.e8. Available from: https://doi.org/10.1016/j.forsciint.2016.02.007
3. Musilová B et al. Exocranial surfaces for sex assessment of the human cranium. J Forensic Sci Int. 2016 [cited 2019 Jun 21]; 269: 70-7. Available from: https://doi.org/10.1016/j.forsciint.2016.11.006
4. Bhayya H; Tejasvi ML; Jayalakshmi B; Reddy M. Craniometric assessment of gender using mastoid process. J Indian Acad Oral Med Rad. 2018 [cited 2019 Jun 21]; 30: 52-7. Available from: http://www.jiaomr.in/text.asp?2018/30/1/52/230883
5. Colmenares GG et al. Sex estimation from skull base radiographs in a contemporary Colombian population. J Forensic and Legal Med. 2019; 62: 77-81. Available from: https://doi.org/10.1016/j.jflm.2019.01.006
6. Deepali J; Jasuja OP; Nath S. Sex determination of human crania using Mastoid triangle and Opisthion-Bimastoid triangle. J Forense Leg Med. 2013; 20(4):255-9. Available from: DOI: 10.1016 / j.jflm.2012.09.020
7. Fatah EEA, Shirley NR, Jantz RL, Mahfouz MR. Improving Sex Estimation from Crania Using a Novel Three-dimensional Quantitative Method. J Forensic Sci. 2014; 59(3): 590-600. Available from: https://doi.org/10.1111/1556-4029.12379
8. Paiva LAS; Segre M. Sexing the human skull through the mastoid process. Rev Hosp Clin 2003 [On-line] [cited 2019 Jun 22]; 58(1). Available from: http://dx.doi.org/10.1590/S0041-87812003000100004
1 De acordo com as normas da UNICAMP/FOP, baseadas na padronização do International Committee of
9. Madadin M, Menezes RG, Dhafeeri O Al, Kharoshah MA, Ibrahim R Al, Nagesh KR, et al. Evaluation of the mastoid triangle for determining sexual dimorphism: A Saudi population-based study. Forensic Sci Int. 2015; 254: 244.e1-244.e4. Available from: https://doi.org/10.1016/j.forsciint.2015.06.019
10. Singh PK, Menezes RG, Shetty BSK, Rastogi P, Kanchan T, Rao J et al. Morphometric sex determination from mastoid triangle in South Indian population. Health Renaissance. 2015;13(2): 105-113. Available from: DOI:10.3126 / hren. v13i2.17559
11. Jung H, Woo EJ. Evaluation of Mastoid Process as Sex Indicator in Modern White Americans using Geometric Morphometrics. J Forensic Sci. 2016; 61(4): 1029-33. Available from: DOI:10.1111/1556-4029.13079
12. Kramer NA et al. Sex estimation from the mastoid process using Micro-CT among Brazilians: Discriminant analysis and ROC curve analysis. J Forensic Rad Imag. 2018; 14: 1-7. Available from: https://doi.org/10.1016/j.jofri.2018.05.003
13. Ibrahim A, Alias A, Shafie MS, Das S, Mohd. Nor F. Osteometric estimation of sex from mastoid triangle in Malaysian population. Asian Journal of Pharmaceutical and Clinical Research.2018; 11(7): 303-307. Available from: https://doi.org/10.22159/ajpcr.2018.v11i7.25986
14. Sinhorini PA et al. Comparative analysis of four morphometric methods for sex estimation: A study conducted on human skulls. Legal Medicine. 2019; 33: 29-34. Available from: https://doi.org/10.1016/j.legalmed.2019.06.001
15. Yilmaz et al. ME. The evaluation of morphometry of the mastoid process using multidetector computed tomography in a living population. J Craniofac Surg. 2015;26(1):259–63.
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ANEXO 1 – Comprovante de Submissão
*O presente artigo foi submetido para apreciação no periódico internacional “Australian Journal of Forensic Sciences”.
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