Sex Determination in Mandibles in the First Year of Life by a Quantitative Approach

Abstract

SUMMARY:Numerous studies have shown that skeletal characteristics vary among different populations. Several authors suggest that it is possible to determine sex through the anatomical evaluation of children mandible, however there are few morphometrical studies conducted with such specimens. The purpose of this study was to analyze several mandibular dimensions and identify the ones that could be useful to perform sex differentiation in a sample of Brazilian young children. For this study we used 32 children dry mandibles of known sex, age ranging from 0 to 1 year old. The mandibles pertain to the collection of the Skull Museum of the Universidade Federal de São Paulo (UNIFESP). The parameters included bicondilar width, bigonial width, minimum width and height of the mandibular ramus, gonion-gnation length, height of the mandibular symphysis and transverse and anteroposterior condylar dimensions. The SPSS program was used to carry on the discriminant function analysis and the T test (p <0.05). There were no statistically significant differences that could allow identification of a specific parameter for sex determination. However, most of the dimensions were higher in male than in female, except for the minimum width of the mandibular ramus (0.2-0.16 mm) and transverse diameter of the right condyle (0.16mm). The values obtained for the anteroposterior diameter of the mandibular head were the most different between genders, although no statistically significance was found. Discriminant function analysis indicated that, despite differences, none of the evaluated parameters allow for sex classification with enough reliability. In conclusion, there is little sexual dimorphism in children's mandibles during the first year of life and anatomical analysis of this structure is not recommended as reliable quantitative approach for sex differentiation with forensic purposes.

Is there enough evidence so that mandible can be used as a tool for sex dimorphism? A systematic review

“…[45678910111213141516171819] And synopsis of skeletal parameters of morphometric studies on dry mandible in sex dimorphism was presented in Table 2. [12202122232425262728293031323334353637]…”

Voyaging into the third dimension: A perspective on virtual methods and their application to studies of juvenile sex estimation and the ontogeny of sexual dimorphism

“…These features impact the extent and magnitude of variation in skeletal shape and size, and as a result quantitative methods have yielded lower success rates when cross-applied. For instance, quantitative traits of the mandible first developed on an African population (Dart Collection) [51], were found to perform poorly when tested on other populations [52,53] or to lack dimorphism 6 [54]. Similarly, tests [55,56] of Weaver's [57] methods, based on sacro-iliac joint morphology, did not achieve similar levels of accuracy.…”

El Dimorfismo Sexual en Distintas Relaciones Cráneo-Mandibulares

“…Diversos estudios han señalado que la altura facial, largo del cuerpo de la mandíbula y altura y ancho de la rama de la mandíbula son variables sexualmente dimórficas (Suazo et al, 2009;Binnal & Devi, 2012;Baccetti et al, 2005), es decir, que la morfología mandibular varía según el sexo (i.e. Al-shamout et al, 2012;Suazo & Zavando, 2012;Kharoshah et al, 2010;Loth & Henneberg, 1996;Franklin et al, 2007), por lo que es utilizada como parámetro para la estimación del sexo en ciencias forenses (Krenzer; Buikstra & Ubelaker).…”