Estimating sex from the seven cervical vertebrae: An analysis of two European skeletal populations.

Methods for estimating sex from a variety of skeletal elements is vital in forensic anthropology as many of the traditionally studied bones are often fragmented upon recovery. The current study examined the seven cervical vertebrae to establish an accurate sex estimation method for Europeans. Discriminant functions were developed from the seven cervical vertebrae using the maximum body height (CHT), vertebral foramen anterior-posterior diameter (CAP), and vertebral foramen transverse diameter (CTR). To date, no study has used these variables to estimate sex from human remains. Two hundred and ninety-five adult individuals (157 males, 138 females) from the University of Athens and the Luis Lopes skeletal collections were studied. No population differences were exhibited between the contemporary Greek and historic Portuguese skeletons, indicating that discriminant functions for sex estimation from the cervical vertebrae may not be population- or temporally-specific. The results of this study indicate that only CHT and CTR exhibited statistically significant sexual dimorphism. Seven multivariate discriminant functions were developed with accuracy rates between 80.3% and 84.5%. Cross-validation studies showed that five of the seven functions exhibited strong statistical algorithms. This study will assist with estimating the sex of unknown Europeans from the cervical vertebrae especially in cases where more accurate predictors of sex, such as the skull or the pelvis, are unavailable.

The influence of biological affinity and sex on morphometric parameters of the clavicle in a South African sample.

OBJECTIVES: The present study aims to investigate the influence of environmental and functional factors associated with biological affinity and musculature on sexual dimorphism of the clavicle, and to develop population-specific methods of sex estimation from the clavicle. METHODS: The maximum length of the clavicle (MAXL), the sagittal diameter of the clavicle (SAGD), and the vertical diameter of the clavicle (VERD) were measured. The left clavicles of 198 South African coloured individuals (108 males and 90 females) were examined. RESULTS: Overall, the results of this study indicate that the SAGD of the clavicle is more sexually dimorphic than the VERD in the South African coloured sample. When the black American, white American, and Greek discriminant functions were applied to the South African coloured metric data, females were more accurately classified than males overall. Population-specific discriminant functions were created for the South African coloured sample. The original accuracy showed that females (85.5%) were more accurately classified than males (78.1%). Overall, the multivariate discriminant function demonstrated a higher correct classification of South African coloureds than the univariate discriminant functions. The results also suggest that univariate discriminant function equations are more accurate for sex estimation than univariate sectioning points in the South African coloured sample. CONCLUSIONS: Overall, the results of the present study indicate that the clavicle is an accurate predictor of sex and its dimensions are population-specific. Therefore, discriminant functions of the clavicle should only be used for sex estimation in forensic anthropology with the populations from which they were derived. © 2018 Wiley Periodicals, Inc.

Is "Latin American" population-specific? Testing sex discriminant functions from the Mexican tibia on a Chilean sample.

Latin American populations are traditionally reported as one ancestral group in the forensic anthropology literature. However, this study illustrates the need for population-specific methodologies for ancestral groups that are considered Latin American. This project evaluated the accuracy of the sex estimation discriminant function created from the tibia of a Mexican population, when applied to a Chilean population. The maximum distal epiphyseal breadth (MDEB) and the anterior-posterior diameter at the nutrient foramen (APDNF) were measured on 203 tibiae (108 males and 95 females) from the Subactual Skeletal Collection at the University of Chile. The individuals ranged in age from 20 to 96 years old. When the Mexican discriminant function was applied to the Chilean population, accuracy rates ranged from 76.0% (males) to 85.0% (females). Mean tibial size comparisons were made to a Mexican, Croatian, White South African, archaeological Hispanic, and North Indian population and showed some significant differences between the variables measured. Population-specific discriminant functions were created for the Chilean population with overall sex classification accuracy rates of 71.4% (MDEB only) to 89.2% (MDEB and APDNF). This study illustrates the need for population-specific and temporally-specific discriminant functions for estimation of sex from the tibia.

Sex estimation from the patella in an African American population.

The skull and pelvis have been used for the estimation of sex for unknown human remains. However, in forensic cases where skeletal remains often exhibit postmortem damage and taphonomic changes the patella may be used for the estimation of sex as it is a preservationally favoured bone. The goal of the present research was to derive discriminant function equations from the patella for estimation of sex from an historic African American population. Six parameters were measured on 200 individuals (100 males and 100 females), ranging in age from 20 to 80 years old, from the Robert J. Terry Anatomical Skeleton Collection. The statistical analyses showed that all variables were sexually dimorphic. Discriminant function score equations were generated for use in sex estimation. The overall accuracy of sex classification ranged from 80.0% to 85.0% for the direct method and 80.0%-84.5% for the stepwise method. Overall, when the Spanish and Black South African discriminant functions were applied to the African American population they showed low accuracy rates for sexing the African American sample. However, when the White South African discriminant functions were applied to the African American sample they displayed high accuracy rates for sexing the African American population. The patella was shown to be accurate for sex estimation in the historic African American population.

Sex estimation from measurements of the calcaneus: Applications for personal identification in Thailand.

As a coastal region, Thailand has been significantly affected by climate change. The impacts of climate change in Thailand - temperature increase, rising sea levels, and violent flooding - are predicted to multiply in both frequency and intensity in the next few decades, which may cause an increase in mass disasters and fatalities in the region. The 2004 tsunami catastrophe in Thailand demonstrated the lack of forensic anthropology expertise and the lack of population specific methods in the region. The goal of this research is to derive population specific discriminant functions from the calcaneus for sexing unidentified skeletal remains from a contemporary Thai population. Nine variables of the calcaneus were measured from 232 individuals (116 males and 116 females) of the Chiang Mai skeletal collection with age ranges from 22 to 96 years. All nine calcanei variables were sexually dimorphic. Multivariate and univariate discriminant function analyses were completed. The multivariate analyses showed accuracy rates from 81.5% to 87.7% in males and 84.0% to 87.7% in females. The accuracy rates from the univariate analyses ranged from 71.6% to 84.0% in males and 67.9% to 85.2% in females. Comparisons to other populations were made and the results demonstrated the need for population specific discriminant functions. Overall, the cross-validation accuracies ranged from 73.4% to 94.3% with males identified correctly more often than females. This study demonstrates that the calcaneus is useful for sex estimation in the contemporary Thai population.

Sex estimation from the scapula in a contemporary Thai population: Applications for forensic anthropology.

The impact of climate change is estimated to be particularly severe in Thailand. Overall, the country faces an increase in surface temperatures, severe storms and floods, and a possible increase in the number of mass disasters in the region. It is extremely important that forensic scientists have access to sex estimation methods developed for use on a Thai population. The goal of this project is to evaluate the accuracy of sex estimation discriminant functions, created using contemporary Mexican and Greek populations, when applied to a contemporary Thai sample. The length of the glenoid cavity (LGC) and breadth of the glenoid cavity (BGC) were measured. The sample included 191 individuals (95 males and 96 females) with age ranges from 19 to 96years old. Overall, when the Mexican and Greek discriminant functions were applied to the Thai sample they showed higher accuracy rates for sexing female scapulae (83% to 99%) than for sexing male scapulae (53% to 92%). Size comparisons were made to Chilean, Mexican, Guatemalan, White American, and Greek populations. Overall, in males and females of the Thai sample, the scapulae were smaller than in the Chilean, Mexican, White American, and Greek populations. However, the male and female Thai scapulae were larger than in the Guatemalan sample. Population-specific discriminant functions were created for the Thai population with an overall sex classification accuracy rate of 83% to 88%.

Determination of sex from the patella in a contemporary Spanish population.

The skull and pelvis have been used for the determination of sex for unknown human remains. However, in forensic cases where skeletal remains often exhibit postmortem damage and taphonomic changes the patella may be used for the determination of sex as it is a preservationally favoured bone. The goal of the present research was to derive discriminant function equations from the patella for estimation of sex from a contemporary Spanish population. Six parameters were measured on 106 individuals (55 males and 51 females), ranging in age from 22 to 85 years old, from the Granada Osteological Collection. The statistical analyses showed that all variables were sexually dimorphic. Discriminant function score equations were generated for use in sex determination. The overall accuracy of sex classification ranged from 75.2% to 84.8% for the direct method and 75.5%-83.8% for the stepwise method. When the South African White discriminant functions were applied to the Spanish sample they showed high accuracy rates for sexing female patellae (90%-95.9%) and low accuracy rates for sexing male patellae (52.7%-58.2%). When the South African Black discriminant functions were applied to the Spanish sample they showed high accuracy rates for sexing male patellae (90.9%) and low accuracy rates for sexing female patellae (70%-75.5%). The patella was shown to be useful for sex determination in the contemporary Spanish population.

Sex estimation from the scapula in a contemporary Chilean population.

The scapula is valuable for sex estimation in human skeletons. Muscles provide protection to the scapula making it difficult to fracture, therefore increasing the potential for undamaged scapulae at forensic scenes. The goal of this project is to evaluate the accuracy of discriminant functions, created using an indigenous Guatemalan and contemporary Mexican population, when applied to a contemporary Chilean sample for estimation of sex from the scapula. The length of the glenoid cavity (LGC) and breadth of the glenoid cavity (BGC) were measured. The sample included 114 individuals (58 males and 56 females) with age ranges from 17 to 85years old. When the Guatemalan discriminant functions were applied to the Chilean sample they showed higher accuracy rates for sexing male scapulae (89.6% to 94.8%) than for sexing female scapulae (53.4% to 80.3%). When the Mexican discriminant functions were applied to the Chilean sample they showed higher accuracy rates for sexing female scapulae (82.1% to 96.4%) than for sexing male scapulae (56.9% to 89.6%). Size comparisons were made to a Guatemalan, Mexican, White American, and Greek population. Overall, in males and females of the Chilean population both left and right scapulae were larger than in the Guatemalan population but smaller than in the Mexican, White American, and Greek samples. Population-specific discriminant functions were created for the Chilean population with an overall sex classification accuracy rate of 80.7% to 86.0%.

Sex determination using the mesio-distal dimension of permanent maxillary incisors and canines in a modern Chilean population.

The pelvis and skull have been shown to be the most accurate skeletal elements for the determination of sex. Incomplete or fragmentary bones are frequently found at forensic sites however teeth are often recovered in forensic cases due to their postmortem longevity. The goal of the present research was to investigate sexual dimorphism between the mesio-distal dimension of the permanent maxillary incisors and canines for the determination of sex in a contemporary Chilean population. Three hundred and three dental models (126 males and 177 females) from individuals ranging in age from 13 years to 37 years old were used from the School of Dentistry, University of Chile. The statistical analyses showed that only the central incisors and canines were sexually dimorphic. Discriminant function score equations were generated for use in sex determination. The average accuracy of sex classification ranged from 59.7% to 65.0% for the univariate analysis and 60.1% to 66.7% for the multivariate analysis. Comparisons to other populations were made. Overall, the accuracies ranged from 54.4% to 63.3% with males most often identified correctly and females most often misidentified. The determination of sex from the mesio-distal width of incisors and canines in Chilean populations does not adhere to the Mohan and Daubert criteria and therefore would not be presented as evidence in court.

Determination of sex from the hyoid bone in a contemporary White population.

Six discriminant functions, developed from an historic White population, were tested on a contemporary White population for determination of sex from the hyoid. One hundred and thirty four fused and unfused hyoids from a contemporary White population were used. Individuals ranged between 20 and 49 years old. Six historic White discriminant functions were applied to the fused and unfused hyoids of the pooled contemporary White population, i.e. all males and females and all age ranges combined. The overall accuracy rates were between 72.1% and 92.3%. Correct sex determination for contemporary White males ranged between 88.2% and 96.3%, while correct sex determination for contemporary White females ranged between 31.3% and 92.0%. Discriminant functions were created for the contemporary White population with overall mean accuracy rates between 67.0% and 93.0%. The multivariate discriminant function overall accuracy rates were between 89.0% and 93.0% and the univariate discriminant function overall accuracy rates were between 67.0% and 86.8%. The contemporary White population data were compared to other populations and showed significant differences between many of the variables measured. This study illustrated the need for population-specific and temporally-specific discriminant functions for determination of sex from the hyoid bone.

Sex determination in a contemporary Mexican population using the scapula.

The scapula is useful for sex determination in human skeletons. Muscles provide protection to the scapula making it difficult to fracture, therefore increasing the potential for undamaged scapulae at forensic scenes. The goal of this project is to evaluate the accuracy of discriminant functions, created using an indigenous Guatemalan population when applied to a contemporary Mexican sample for determination of sex from the scapula. The length of the glenoid cavity (LGC) and breadth of the glenoid cavity (BGC) were measured. The sample included 177 individuals (101 males and 76 females) with age ranges from 21 to 100 years old. When the Guatemalan discriminant functions were applied to the Mexican sample they showed high accuracy rates for sexing male scapulae (100%) and low accuracy rates for sexing female scapulae (48.68%-51.32%). Size comparisons were made to an indigenous Guatemalan sample and a contemporary White sample. Overall, LGC and BGC were larger in the Mexican sample than in the Guatemalan sample but LGC and BGC were smaller in the Mexican sample than in the White sample. Population-specific discriminant functions were created for the Mexican population with an overall sex classification accuracy rate of 83.6%-89.3%.

Sex determination from the calcaneus in a 20th century Greek population using discriminant function analysis.

The skull and post-cranium have been used for the determination of sex for unknown human remains. However, in forensic cases where skeletal remains often exhibit postmortem damage and taphonomic changes the calcaneus may be used for the determination of sex as it is a preservationally favored bone. The goal of the present research was to derive discriminant function equations from the calcaneus for estimation of sex from a contemporary Greek population. Nine parameters were measured on 198 individuals (103 males and 95 females), ranging in age from 20 to 99 years old, from the University of Athens Human Skeletal Reference Collection. The statistical analyses showed that all variables were sexually dimorphic. Discriminant function score equations were generated for use in sex determination. The average accuracy of sex classification ranged from 70% to 90% for the univariate analysis, 82.9% to 87.5% for the direct method, and 86.2% for the stepwise method. Comparisons to other populations were made. Overall, the cross-validated accuracies ranged from 48.6% to 56.1% with males most often identified correctly and females most often misidentified. The calcaneus was shown to be useful for sex determination in the twentieth century Greek population.

Sex estimation using diagonal diameter measurements of molar teeth in African American populations.

Teeth are often recovered in forensic cases due to their postmortem longevity. The goal of the present research was to investigate the degree of sexual dimorphism in the permanent molars of African Americans using crown and cervical diagonal diameters. Discriminant functions developed from a modern Greek population were tested for accuracy of sex estimation in an African American population. One hundred and three (53 males and 50 females) individuals ranging in age from 16 years to 66 years old were used from the Robert J. Terry Anatomical Skeletal Collection. Four diagonal diameter measurements were taken for each of the left mandibular and maxillary molars: mesiobuccal-distolingual crown diameter, mesiolingual-distobuccal crown diameter, mesiobuccal-distolingual cervical diameter, and mesiolingual-distobuccal cervical diameter. The overall percentage of accuracy of the modern Greek discriminant functions when applied to the African American sample was between 53.8% and 63.6%. Males were more accurately classified (93.6%-100%) than females (0%-18.2%). The African American population specific direct discriminant functions showed accuracy rates from 72.6% to 100% for the original data and 40%-72.3% for the cross-validated data. The African American stepwise discriminant functions showed accuracy rates from 63.9% to 77.6% for the original and cross-validated data. Comparisons to other populations were made. The results suggest that, in teeth, there is variation in the degree of sexual dimorphism between populations and discriminant functions for sex estimation in dentition are population specific.

Sex determination from the talus in a contemporary Greek population using discriminant function analysis.

The determination of sex is an important part of building the biological profile for unknown human remains. Many of the bones traditionally used for the determination of sex are often found fragmented or incomplete in forensic and archaeological cases. The goal of the present research was to derive discriminant function equations from the talus, a preservationally favoured bone, for sexing skeletons from a contemporary Greek population. Nine parameters were measured on 182 individuals (96 males and 86 females) from the University of Athens Human Skeletal Reference Collection. The individuals ranged in age from 20 to 99 years old. The statistical analyses showed that all measured parameters were sexually dimorphic. Discriminant function score equations were generated for use in sex determination. The average accuracy of sex classification ranged from 65.2% to 93.4% for the univariate analysis, 90%-96.5% for the direct method and 86.7% for the stepwise method. Comparisons to other populations were made. Overall, the cross-validated accuracies ranged from 65.5% to 83.2% and males were most often correctly identified. The talus was shown to be useful for sex determination in the modern Greek population.

In vivo facial tissue depth for Canadian Mi'kmaq adults: a case study from Nova Scotia, Canada.

This study examines facial tissue depth in Canadian Mi'kmaq adults. Using ultrasound, measurements were taken at 19 landmarks on the faces of 152 individuals aged 18-75 years old. The relationships between tissue thickness, age, and sex were investigated. A positive linear trend exists between tissue thickness and age for Mi'kmaq males and females at multiple landmarks. Seven landmarks show significant differences in facial tissue depth between males and females aged 18-34 years old; no landmarks show significant differences in facial tissue depth between males and females aged 35-45 years old and 46-55 years old. Significant differences were shown in facial tissue depth between Mi'kmaq and White Americans and Mi'kmaq and African Americans. These data can assist in 3-D facial reconstructions and aid in establishing the identity of unknown Mi'kmaq individuals.

In vivo facial tissue depth for Canadian aboriginal children: a case study from Nova Scotia, Canada.

This study examines facial tissue depth in Canadian Aboriginal children. Using ultrasound, measurements were taken at 19 points on the faces of 392 individuals aged 3-18 years old. The relationships between tissue thickness, age, and sex were investigated. A positive linear trend may exist between tissue thickness and age for Aboriginal females and males at multiple points. No points show significant differences in facial tissue depth between males and females aged 3-8 years old; seven points show significant differences in facial tissue depth between males and females aged 9-13 years old; and five points show significant differences in facial tissue depth between males and females aged 14-18 years old. Comparisons were made with White Americans and African Nova Scotians. These data can assist in 3-D facial reconstructions and aid in establishing an individual's identity. Previously, no data existed for facial tissue thickness in Canadian Aboriginal populations.