A geometric morphometric study into the sexual dimorphism of the human scapula (original) (raw)
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Forensic Sciences
The estimation of biological sex is of paramount relevance in the analysis of skeletal remains recovered in forensic contexts. This study aims to assess sexual dimorphism for identification purposes, from two reference samples of the Portuguese population, and a depiction of the size- and shape-related sexual dimorphism of the human scapula using geometric morphometrics approaches. The sample comprised 211 individuals (100 males and 111 females). A generalized Procrustes analysis (GPA) was performed for shape analyses, a principal component analysis (PCA) and a Procrustes ANOVA were implemented on the GPA transformed variables, and a discriminant analysis was used to assess the cross-validated accuracy of sex estimates. The data showed that male scapulae were larger, with medial and lateral curves more pronounced and an inferior angle more acute than females. The males and females were classified with low accuracy (66.82% and 65.88% for landmarks and semi-landmarks data) based on sh...
Morphometric Analysis of the Scapula and Their Differences between Females and Males
International Journal of Morphology, 2016
Sexual dimorphism is a key role for forensic anthropology. It allows ascertaining the sex of certain biological discoveries. By postmortem studies it is possible to establish a profile of individuals. This profile allows the identification in cases where bodies are skeletonized. Several bones present dimorphism and have been studied to increase approach for forensic identification. This study morphometrically evaluated the scapula bone and compared the measurements between scapula bone of female and male cadavers. Sixty parts were utilized in this experiment. All cadavers belonged to the Department of Animal Morphology and Physiology of the Federal Rural University of Pernambuco. The scapula bones were photographed and measured through software ImageJ®. Eight parameters of measurements were considered: scapula height (SH), distance between basis and spine (DBSp), scapula width (SW), spine width (SpW), acromion-coracoid width (ACW) and scapula body width at 2 (L2), 4 (L4) and 6 (L6) cm of the lower angle. The median morphometric values for the male scapulas were: SH
Morphometric analysis of scapula to determine sexual dimorphism
International Journal of Medicine and Public Health, 2013
Background and Objectives: Identifi cation of the sex of an individual is important in determining, the identity from the available parts of skeleton. Aims: To derive a logistical regression formula for sex determination of Indian population, using dimensions of scapula. Materials and Methods: Thirty one adult scapulae (20 males and 11 females) were used in the study. Scapulae were measured in millimetre for MSH, MSB, GCH and GCB with the help of the sliding calliper. The logistical regression equation was derived from these measurements. Results: Among all parameters, MSB found to be most signifi cant (P ≤ 0.001). For the regression equation incorporating all for Scapular dimensions, the logistic regression score (Y) is calculated as follow: Y = (-0.246*MSH) + (0.122*MSB) + (-0.486*GCH) + (-0.034*GCB) +35.356. Conclusion: The results of this study are very useful for sex determination in medicolegal cases where the skulls and pelvic bones are damaged or not available. In this study, population specifi c logistic regression formula is derived by combination of parameters, which can be helpful for sex determination in Indian populations.
A Method for Estimating Sex Using Metric Analysis of the Scapula
Journal of Forensic Sciences, 2010
Abstract: The most accurate and precise methods for the assessment of age and stature often require knowledge of sex. Thus, being able to correctly identify sex from skeletal remains is critical in the forensic context. The presence of the os coxae or skull can never be guaranteed, making the development of reliable methods of sex estimation using other skeletal elements necessary. Using a 724 individual calibration sample from the Hamann-Todd collection, this study identifies sexual dimorphism in the human scapula, and presents a new five-variable discriminant function for sex estimation. The overall accuracy of this method proved to be 95.7% on the cross-validated calibration sample, 92.5% on an 80 individual test sample from the Hamann-Todd collection, and 84.4% on a 32 individual test sample from the skeletal collection of the Wichita State University Biological Anthropology Laboratory. Additionally, a slightly less accurate two-variable model was developed and has cross-validated accuracy of 91.3%.
TECHNICAL NOTE ANTHROPOLOGY A Method for Estimating Sex Using Metric Analysis of the Scapula*
The most accurate and precise methods for the assessment of age and stature often require knowledge of sex. Thus, being able to correctly identify sex from skeletal remains is critical in the forensic context. The presence of the os coxae or skull can never be guaranteed, making the development of reliable methods of sex estimation using other skeletal elements necessary. Using a 724 individual calibration sample from the Hamann-Todd collection, this study identifies sexual dimorphism in the human scapula, and presents a new five-variable discriminant function for sex estimation. The overall accuracy of this method proved to be 95.7% on the cross-validated calibration sample, 92.5% on an 80 individual test sample from the Hamann-Todd collection, and 84.4% on a 32 individual test sample from the skeletal collection of the Wichita State University Biological Anthropology Laboratory. Additionally, a slightly less accurate two-variable model was developed and has cross-validated accuracy of 91.3%.
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 85 years 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%.
Biology
Fibular metric variations have revealed their potential in distinguishing between males and females; however the fibula remains scarcely analyzed in studies of sexual dimorphism. This work aims at investigating sexually dimorphic features in fibular proximal and distal epiphyses through geometric morphometrics methods. A total of 136 left fibulae, from two Italian and one South African identified skeletal collections were virtually acquired through CT and laser scanning and analyzed using geometric morphometric methods. Statistical analyses were performed on shape, form, and size variables. Results show that fibular epiphyses are smaller with narrower articular surfaces in females than in males in both extremities. Relevant sexual differences emerge in fibular form and size for the two Italian samples but not for the South African one, likely for its small sample size. Discriminant analysis on form principal components (PCs) offers accuracy above 80% when the samples are pooled, and...
Sexual Dimorphism in the Subadult Mandible: Quantification Using Geometric Morphometrics
Journal of Forensic Sciences, 2007
There have been numerous attempts, with varying degrees of success, to differentiate males from females on the basis of the immature skeleton. We investigate here whether the mandible can discriminate immature individuals by sex; the techniques we apply are from the field of geometric morphometrics. The application of these methods in forensic anthropology is still relatively new; thus, an important aspect of this research is that it demonstrates potential applications in this discipline. The sample comprises 96 known age and sex subadult individuals; the three-dimensional coordinates of 38 landmarks are analyzed using the shape analysis software morphologika. Multivariate regressions indicated no significant sexual dimorphism in the subadult sample; this result is supported by poor cross-validated classification accuracy (59%). Our results suggest that the subadult mandible is not dimorphic (to the extent that dimorphism is not evident within the sample we studied); thus, sex determination using previously described criteria is likely to yield poor results.
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%e51.32%). 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%.