Sexing the Cranium from the Foramen Magnum Using Discriminant Analysis in a Brazilian Sample

Abstract

In the identification process, the foramen magnum has shown controversial results in sex estimation. The present study aimed to analyze the morphometric variables of the foramen magnum in Brazilian adult cranium for sex estimation. The sample was composed of 100 craniums (53 males and 47 females) from the documented collection of the Institute of Teaching and Research in Forensic Sciences. The protocol measurement was constituted of two linear measurements: maximum length of the foramen magnum and maximum breadth of the foramen magnum and two formulas to calculate the area, method one (M1) and method two (M2). Descriptive statistics showed statistically significant differences between sex (p<0.05) for all variables. The univariate discriminant functions showed an accuracy between 56.0-62.0%, and the multivariate analysis showed a percentage of accuracy between 60.0-65.0%, the greatest accuracy was found combining the two linear measurements with M1(71.7%), even after cross-validation (66%). Receiver Operating Characteristic (ROC) curve analysis showed that M2 is the best parameter for estimating sex (AUC=0.693). A reference table for Brazilians using the foramen magnum parameters was developed based on the results of the ROC curve analysis. In conclusion, the foramen magnum should be used with caution to estimate sex in forensic cases of fragmentary craniums, due to the limited accuracy.

Foramen Magnum as Dimorphic Tool for Sex Determination in the Egyptian population using Cone Beam Computed Tomography: A Retrospective Study

“…It may also be used in cases where DNA testing is not possible because of the damage of the sample remains, as in extensive heat damage. 11,19 To evaluate effect of sex on FM morphometric variables, the sample size of this study was calculated based on (Lopez-Capp et al, 2018; Mustafi et al, 2019) 15,20 , with an actual power (1-β error) of 0.8 (80%) and a significance level (α error) 0.05 (5%) for two-sided hypothesis test.…”

“…25 , who performed FM analysis on human crania and skulls which is not readily available and has some ethical concerns. 5,15,16 Moreover, this study utilized CBCT data because linear measurements obtained from CBCT scans are highly accurate and reproducible. 26 This came in agreement with Akay et al, 2017 who only measured the sagittal and transverse diameters on Turkish population.…”

“…14 (Area = π x [(length + width)/4] 2 ) and referred to as "Area 2". 5,15 However, for performing the FMI, this equation was used as follows: FM width / FM length x 100. 16…”

Usability of first molar teeth measurements for age and sex estimation in cone-beam computed tomography images

“…In other studies, focusing on the cranium, SE has been made by multiple parameters of the maxillary sinus, foramen magnum and mandibular bone and the accuracy rates obtained are consistent with our findings. 25,[31][32][33][34] Based on the data obtained from our study, morphometric analysis of molar teeth with PTVR was considered to be an important parameter for sex determination. As in other skeletal areas, increasing the number of measured parameters in the dentomaxillofacial area may also increase the reliability.…”

Estudo morfológico e morfométrico do Forame Magno e dos Côndilos Occipitais em crânios secos do Mato Grosso do Sul

“…Outro fato que chama a atenção foi a metodologia aplicada no presente estudo, o paquímetro é um dos instrumentos mais utilizados nos estudos com abordagem morfométrica (Cirpan et al, 2016;Lopez-Capp et al, 2018;Pires et al, 2016), e mesmo quando estudos comparam medidas em crânio seco com exames de imagem (tomografia computadorizada), as médias pouco se alteram (Luzzi et al, 2019). Dessa forma, podemos destacar que nossa metodologia, apesar de ser menos complexa, apresenta eficácia.…”