Greater Sciatic Notch as a Sex Indicator in Juveniles (original) (raw)
Related papers
American journal of physical anthropology, 2013
The greater sciatic notch (GSN) is one of the most important and frequently used characteristics for determining the sex of skeletons, but objective assessment of this characteristic is not without its difficulties. We tested the robustness of GSN sex classification on the basis of geometric morphometrics (GM) and support vector machines (SVM), using two different population samples. Using photographs, the shape of the GSN in 229 samples from two assemblages (documented collections of a Euroamerican population from the Maxwell Museum, University of New Mexico, and a Hispanic population from Universidad Nacional Autónoma de México, Mexico City) was segmented automatically and evaluated using six curve representations. The optimal dimensionality for each representation was determined by finding the best sex classification. The classification accuracy of the six curve representations in our study was similar but the highest and concurrently homologous cross-validated accuracy of 92% was achieved for a pooled sample using Fourier coefficient and Legendre polynomial methods. The success rate of our classification was influenced by the number of semilandmarks or coefficients and was only slightly affected by GSN marginal point positions. The intrapopulation variability of the female GSN shape was significantly lower compared with the male variability, possibly as a consequence of the intense selection pressure associated with reproduction. Males were misclassified more often than females. Our results show that by using a suitable GSN curve representation, a GM approach, and SVM analysis, it is possible to obtain a robust separation between the sexes that is stable for a multipopulation sample. Am J Phys Anthropol 152:558-565, 2013. © 2013 Wiley Periodicals, Inc.
Forensic science international, 2008
Although the assignment of sex to immature skeletal remains is considered problematic, some traits have been considered useful for both forensic and bioarchaeological applications. One such trait is the arch criterion found in subadult ilia, which is defined relative to the greater sciatic notch-auricular surface area. In adults, the composite arch has also been described in relation to this area and has proven relatively successful in sex determination. This study offers an examination of the accuracy of the arch criterion and the composite arch in determining the sex of subadult skeletal remains, and an assessment of intra-and inter-observer scoring error. A sample of 97 skeletons of known sex and age (<15 years) from the Lisbon collection (Portugal) were selected and the traits were scored by three observers on orthogonal photos of each ilium. In general the agreement within (67.7-88.5%) and between (50.5-76.3%) examiners was poor and overall accuracy (26.7-52.6%) did not meet the expectations of that reported in previous studies. The authors suggest that this derives from great variation in morphology, difficulties in interpreting criteria and possibly a lack of association between the expression of the traits and sex. Careful examination of sex-related morphology in the immature skeleton and additional blind tests of so-called useful traits should continue to be carried out. #
AN INVESTIGATION OF SEX DETERMINATION FROM THE SUBADULT PELVIS: A MORPHOMETRIC ANALYSIS
The pelvis, the most sexually dimorphic area of the adult human skeleton, is essential to determine biological sex. Although sex differences have been noted in subadult pelvic bones since the late 1800s, no reliable method has been developed to determine biological sex, and therefore, subadult sex demographics must be omitted from forensic and archaeological investigations. This study examined three North American skeletal samples of documented age and sex, the Forensic Fetal Osteological Collection (n=113), the subadult component of the Hamann-Todd Collection (n=37), and the Trotter Fetal Bone Collection (n=37), to test the hypothesis that subadult pelvic traits, both metric and non-metric, are sufficiently sexually dimorphic in one or more sample or age category. Method accuracy and reliability were also evaluated. Traits included those previously studied: the breadth and angle of the sciatic notch, iliac crest curvature, arch criterion, auricular surface elevation, subpubic angle, pubic length, and ischial length. Two additional feature analyses and three indices were developed for this study: the anterior and posterior sciatic notch lengths, pubic body width, pubic index, anterior/posterior sciatic notch, and sciatic notch width/iliac length index. Both left and right sides were considered using photographic and direct measurement techniques. For t-tests and correlations, at least one trait per sample reached statistically significant levels for sexual dimorphism. Reliable testing methods were not developed because these features were inconsistently sexually dimorphic for each sample; furthermore, male and female measurement ranges overlapped considerably, trait morphology proved variable, and individuals were incorrectly assigned to sex when using methods outlined in previous studies. Both logistic regression and discriminant function analysis provided low predictive scores, the highest at 0.68, which were insufficient to predict sex consistently or meet the Daubert threshold. Two non-metric traits, sciatic notch shape and auricular surface elevation, also proved to be inconsistent across the three samples. Consequently, these traits were unreliable for sex determination. Several features, including the sciatic notch width, sciatic notch shape, and pubic body width, demonstrated differences among older subadults and should be investigated using larger, broadly-aged samples that include adults.
International Journal of Osteoarchaeology, 2017
Sex estimation in non-adult skeletons is crucial in bioarchaeology and forensic anthropology. It was not extensively considered in the past, mainly because it was stated that the dimorphic osteological features were difficult to identify before adulthood. Over the past few years, this statement was disproved, and the study of numerous dimorphic non-adult skeletal traits was approached. This paper presents a new methodology that evaluates the auricular surface of the non-adult ilia. Several morphological and continuous variables were recorded for 34 individuals (21 females and 13 males) aged between 7 and 18 from the Coimbra Identified Skeletons Collection (University of Coimbra, Portugal). The results show low intra and inter-observer errors for all the variables, which renders the methodology replicable. Two ratios related to the shape of the anterior area of the auricular surface offer the most dimorphic data (proportions of cases correctly assigned: 0.82 and 0.88; sexual allocation probabilities: 0.85 for both variables). A discriminant function and a logistic regression were developed, which correctly classified the 82.35 and the 88.23% of the individuals, respectively. Moreover, two qualitative variables, referred to as the overall morphology and the apex morphology, also show statistically significant differences between males and females (proportions of correct assignation: 0.82 and 0.76; sexual allocation probabilities: 0.79 and 0.76). These variables can be incorporated in a multifactorial approach together with other indicators already available in the specialised literature in order to help improve the accuracy of the results obtained. This methodological procedure has to be applied with other identified samples, including younger individuals, so as to test whether the trends presented in this context are maintained and are useful in populations from a different geographical provenience.
International Journal of Research in Pharmaceutical Sciences
To identify the sex determination of an unknown person from the skeleton remains the first and primary important step come across by the anatomical, forensic and archaeological experts. Many researchers have considered various parameters for sex determination using hip bone. The current study was carried out to identify the sex of hip bone using various dimensions of the greater sciatic notch. Adult hip bones of a known person were studied and evaluated. The hip bones were assessed using various parameters. The posterior segment, posterior angle and index II of a hip bone were found to be more helpful in sex determination.
A Geometric Morphometric Approach to Sex Estimation of the Greater Sciatic Notch
MSc Dissertation, University of Exeter, 2020
Sex estimation is one of the first analyses carried out on unidentified skeletal remains, and new methods for accurate and reliable sex estimation are constantly being created and tested to determine the sex of unknown individuals. This project was undertaken in order to assess the reliability of morphological scales in comparison to geomorphic morphometric (GMM) techniques for sex estimation of the greater sciatic notch. The study analyses the pelvises of a medieval (11th-15th century AD) skeletal population from Exeter, England to assess the morphology of the greater sciatic notch and its potential for the application of geomorphic morphometric techniques. Currently, sex estimation of the greater sciatic notch is often undertaken using Walker’s standardised ordinal scale, which is based on a modern American population, to assign a specimen as either masculine, feminine or indeterminate. The reliability of this scale on archaeological samples will be assessed to determine the differences in accuracy when applying an ordinal scale versus GMM analyses to the greater sciatic notch. Thus, it is necessary to also determine the viability and reliability of assigning sex in such a way. The results of this study indicate that, by using GMM in conjunction with coding, there are statistically significant differences in male and female greater sciatic notch shape. This study found it was possible to write and execute commands to predict the sex of an individual of unknown sex based solely on their sciatic notch, in tandem with the data gathered from other previously sexed specimens within the same sample.
Technical Note: Geometric Morphometrics and Sexual, 2013
The greater sciatic notch (GSN) is one of the most important and frequently used characteristics for determining the sex of skeletons, but objective assessment of this characteristic is not without its difficulties. We tested the robustness of GSN sex classification on the basis of geometric morphometrics (GM) and support vector machines (SVM), using two different population samples. Using photographs, the shape of the GSN in 229 samples from two assemblages (documented collections of a Euroamerican population from the Maxwell Museum, University of New Mexico, and a Hispanic population from Universidad Nacional Aut onoma de M exico, Mexico City) was segmented automatically and evaluated using six curve representations. The optimal dimensionality for each representation was determined by finding the best sex classification. The classification accuracy of the six curve representations in our study was similar but the highest and concurrently homologous cross-validated accuracy of 92% was achieved for a pooled sample using Fourier coefficient and Legendre polynomial methods. The success rate of our classification was influenced by the number of semilandmarks or coefficients and was only slightly affected by GSN marginal point positions. The intrapopulation variability of the female GSN shape was significantly lower compared with the male variability, possibly as a consequence of the intense selection pressure associated with reproduction. Males were misclassified more often than females. Our results show that by using a suitable GSN curve representation, a GM approach, and SVM analysis, it is possible to obtain a robust separation between the sexes that is stable for a multipopulation sample. Am J Phys Anthropol 152:558-565,
American Journal of Physical Anthropology
The greater sciatic notch (GSN) is one of the most important and frequently used characteristics for determining the sex of skeletons, but objective assessment of this characteristic is not without its difficulties. We tested the robustness of GSN sex classification on the basis of geometric morphometrics (GM) and support vector machines (SVM), using two different population samples. Using photographs, the shape of the GSN in 229 samples from two assemblages (documented collections of a Euroamerican population from the Maxwell Museum, University of New Mexico, and a Hispanic population from Universidad Nacional Autónoma de México, Mexico City) was segmented automatically and evaluated using six curve representations. The optimal dimensionality for each representation was determined by finding the best sex classification. The classification accuracy of the six curve representations in our study was similar but the highest and concurrently homologous cross-validated accuracy of 92% wa...
Dissertation submitted 2010 for the completion of a MSc in human osteology and funerary archaeology, University of Sheffield. 'In this dissertation, an attempt will be made to explore some possible new methods for studying sexual dimorphism in subadults. In previous research, most attention has been given to the study of the ilium and the skull, as these are reliable indicators of sexual dimorphism in adults. However, long bone robusticity has also been explored as a possible indicator of sexual dimorphism in juveniles, as well as ischium morphology. These methods were tested for their applicability and usefulness, as well as one morphological method, which is based on the assessment of the mandible. A sample of 117 juvenile skeletons were included in this study, as these skeletons had good dental preservation and at least one long bone (humerus or femur) or ischium available for measurements. Measurements were most easily repeated on the ischium, as the acetabulum provides a good point of reference. Analysis of the dimensions were carried out using exploratory statistics and cluster analysis. Although it was hoped some sexual dimorphism would be found in the data, most comparisons are not statistically significant, indicating that there is a large amount of overlap between sexes. Ischium dimensions are the most promising of the methods tested (Rissech et al. 2003).'