Sexually dimorphic pelvic morphology in South African whites and blacks

Comparison of Morphological Sex Assessment and Genetic Sex Determination on Adult and Sub-Adult 17th-19th Century Skeletal Remains

The first step in the analysis of human skeletal remains is the establishment of the biological profile of an individual. This includes sex assessment, which depends highly on the age of the individual and on the completeness and preservation state of the remains. Macroscopic methods only provide the assessment of sex, while for sex determination, molecular methods need to be included. However, poor preservation of the remains can make molecular methods impossible and only assessment can be performed. Presented research compares DNA-determined and morphologically assessed sex of adult and non-adult individuals buried in a modern-age cemetery (17th to late 19th century) in Ljubljana, Slovenia. The aim of the study was to assess the accuracy of commonly used macroscopic methods for sex assessment on a Slovenian post-medieval population. Results demonstrate that for adults, macroscopic methods employed are highly reliable and pelvic morphology, even the sciatic notch alone, is more reliable than skull. In non-adults, macroscopic methods are not as reliable as in adults, which agrees with previous research. This study shows how morphological and molecular methods can go hand in hand when building a biological profile of an individual. On their own, each methodology presented some individuals with undetermined sex, while together, sex of all the individuals was provided. Results confirm suitability of sex assessment based on skull and especially pelvic morphology in Slovenian post-medieval adults, while in the non-adult population molecular methods are advised.

Comparison of sex determination using three methods applied to the greater sciatic notch of os coxae in a Thai population: Dry bone morphology, 2-dimensional photograph morphometry, and deep learning artificial neural network

The os coxa is commonly used for sex and age estimation with a high degree of accuracy. Our study aimed to compare the accuracy among three methods, which include a deep learning approach to increase the accuracy of sex prediction. A total sample of 250 left os coxae from a Thai population was divided into a 'training' set of 200 samples and a 'test' set of 50 samples. The age of the samples ranged from 26 to 94 years. Three methods of sex determination were assessed in this experiment: a dry bone method, an image-based method and deep learning method. The intra- and inter-observer reliabilities were also assessed in the dry bone and photo methods. Our results showed that the accuracies were 80.65%, 90.3%, and 91.95% for the dry bone, image-based, and deep learning methods, respectively. The greater sciatic notch shape was wide and symmetrical in females while narrow and asymmetrical in males. The intra- and inter-observer agreements were moderate to almost perfect level (Kappa = 0.67-0.93, ICC = 0.74-0.94). Conclusion: The image-based and deep learning methods were efficient in sex determination. However, the deep learning technique performed the best among the three methods due to its high accuracy and rapid analysis. In this study, deep learning technology was found to be a viable option for remote consultations regarding sex determination in the Thai population.

A geometric morphometric assessment of shape variation in adult pelvic morphology

OBJECTIVES

In humans, the pelvis is the most sexually dimorphic skeletal element and is often utilized in aging and sexing remains. The pelvis has become greatly relied upon in anthropological research (e.g., forensics, demographics, obstetrics, evolutionary history); however, pelvis morphology is highly variable, and very little is known about the nature, sources, patterning, and interpretation of this variation. This study aims to quantify pelvis shape variation, document sexual shape variation, and estimate the plasticity of morphology. This will ultimately give greater ability to interpret modern, archaeological, and evolutionary patterns to gain deeper insight into processes which shape human anatomy.

MATERIALS AND METHODS

Using a sample of 129 Medieval Danish skeletons, shape variation is documented in the greater sciatic notch (GSN), iliac crest (IC), arcuate line (AL), and sub-pubic angle (SPA) using 3D geometric morphometrics. The landmarking method applied here has the advantage of being applicable to fragmentary remains, rather than requiring whole bones. This allows it to be easily applied to archaeological samples and for the interpretation of separate bone features. Differences in shape were statistically analyzed by principle component analysis, linear discriminate analysis, and morphological disparity. Relationships between maximum femur length, body mass, and shape centroid size were also test by allometric regression.

RESULTS

Results quantify the sexual dimorphism and shape variation present in these features. The GSN shape is the most variable, while the AL is the least. Similarly, the IC is the only feature which shows almost no dimorphism in shape, and instead best reflects lifestyle/activity patterns. Evidence of dimorphism in the IC is likely a result of cultural labor patterns rather than genetic and hormonal influence. Finally, the shapes of the GSN, AL, and SPA are more related to body mass than to femur length, such that individuals with increased mass exhibit more classically "male" shapes and those with less mass have more "female" shapes.

DISCUSSION

The results have important implications for the evolution of pelvic anatomy, and sexual dimorphism, but also highlight the plasticity inherent in pelvic morphology. Analyzing pelvis features separately in a clearly defined, relatively genetically homogenous population gives insight into the determinants of bone morphology, which are not readily observable by other means. The relationship between body mass and shape suggests dimorphism in body size and composition may affect bone shape.

Shape morphing technique can accurately predict pelvic bone landmarks

Diffeomorphic shape registration allows for the seamless geometric alignment of shapes. In this study, we demonstrated the use of a registration algorithm to automatically seed anthropological landmarks on the CT images of the pelvis. We found a high correlation between manually and automatically seeded landmarks. The registration algorithm makes it possible to achieve a high degree of automation with the potential to reduce operator errors in the seeding of anthropological landmarks. The results of this study represent a promising step forward in effectively defining the anthropological measures of the human skeleton.

Influence of climatic stress on nonmetric sexually dimorphic features of the skull and pelvis

OBJECTIVES

Human sexual dimorphism is frequently assessed through skull and pelvic size and shape. Researchers suggest that climatic variation and the associated stress may be significant factors in sexual dimorphism's etiology. However, little research has specifically investigated climatic effects on nonmetric skeletal indicators of sex. To further appreciate the plasticity of human biology, a comparative study of standard skull and pelvic nonmetric sex indicators is presented.

METHODS

A Native Alaskan archeological sample (n = 104) and a component of the Terry collection (n = 99) represent populations originating from different climatic environments in recent history. These sex-balanced groups are compared through Tukey-Kramer's method and Greene's t-test to determine any variation in degree of sexual dimorphism within and between samples.

RESULTS

The results reinforce the complex and multifaceted relationship between climate and sexual dimorphism. The Terry sample demonstrated a greater degree of sexual dimorphism with statistically significant differences in robusticity of the mastoid process and nuchal crest compared with the Native Alaskans. A more "male" morphotype and reduced dimorphism are appreciated in the pelves of Native Alaskans than the Terry sample.

CONCLUSIONS

This research highlights a reduction in sexual dimorphism in populations under greater climatic stress and contributes to the production of more accurate skeletal assessments in future investigations. Discussion of confounding factors suggest more research is necessary to untangle climate and human morphology's complex relationship. This study contributes to a greater appreciation of human biological plasticity, ecogeographic variation, and the evolution of modern human diversity.

Accuracies of discriminant function equations for sex estimation using long bones of upper extremities

One of the scopes of practice of forensic anthropologists is the estimation of sex from skeletal remains. As a result, population-specific discriminant function equations have been developed from measurements of various bones of the human skeletons. Steyn, Patriquin (Forensic Sci Int 191 (1-3):113, 2009) noted that the lack of skeletal collections and data from most parts of the world has made this process impractical. Previous attempts to develop global discriminant function equations from measurements of the pelvis showed that population-specific equations are not necessary as equations derived from other populations yielded high sex estimation scores when applied to a different population. However, information on the suitability and applicability of generalised equations in sex estimation using long bones is still scarce. It is, therefore, the aim of this study to assess the accuracies of population-specific discriminant function equations derived from measurements of long bones of the upper limb of South African population groups. Data analysed in the current study were obtained from Mokoena, Billings, Bidmos, Mazengenya (Forensic Sci Int 278:404, 2017) and Mokoena, Billings, Gibbon, Bidmos, Mazengenya (Science & Justice 6(59):660-666, 2019) in which a total sample of 988 bones (humeri, radii, and ulnae) of South Africans of African descent (SAAD), South Africans of European descent (SAED) and Mixed Ancestry South Africans (MASA) were measured. Stepwise and direct discriminant function analyses were performed on the pooled data. Each function was used to estimate the sex of cases in each population group separately and average accuracies calculated. Thereafter, population-specific discriminant function equations were formulated for each population group and then applied to other population groups. The average accuracies of functions for pooled data ranged between 80.7 and 86.5%. The cross-validation average accuracies remained unchanged for most functions, confirming the validity of derived functions. A drop in average accuracies (0.8-5.3%) was observed when the functions were tested on a sample of SAAD while increased average accuracy was observed for the SAED and MASA (0.5-6.9%). When population-specific functions for a particular population group were applied to other groups, a wide range of a drop in average accuracies was observed (1.3 to 22.4%). This thereby confirms that population-specific equations should not be applied to other population groups. However, discriminant function equations from the pooled data of South Africans are accurate in the estimation of sex and efforts should be made towards the development and validation of such equations from as many bones of the human skeleton.

Evaluation of the auricular surface method for subadult sex estimation on Italian modern (19th to 20th century) identified skeletal collections

OBJECTIVES

Sex estimation in subadult skeletal remains is still considered highly problematic. The aim of this research is to test the reliability of the method of subadult sex assessment proposed by Luna and co-workers in 2017, based on the analysis of the auricular surface of the ilium.

MATERIALS AND METHODS

Seven ratios and three morphological traits were recorded for 127 subadult individuals (63 males and 64 females), aged between 0 and 17 years, from several Identified Skeletal Collections of the University of Bologna. Nonparametric Mann Whitney test, Kolmogorov Smirnov test, and the Pearson correlation coefficient were used for continuous variables, whereas the Cramer Coefficient was calculated for qualitative variable. A principal component analysis was also performed on ratio values. The statistic ƞ was taken into account for both types of variables.

RESULTS

None of the ratios presented significant dimorphic results. Two qualitative variables show statistically significant differences between sexes. The overall morphology proved to be an accurate sex predictor among children aged ≥4 years (78%-86%) and meets the minimum accuracy standard (75%) for subadult sex estimation for individuals between 1 and 17 years of age. The morphology of the retroauricular end of the superior demiface (MRS) can be used with a high level of accuracy for sexing individuals from 1 to 12 years (77%-81%).

CONCLUSIONS

The metric variables did not replicate the accuracy values originally obtained by Luna and co-workers. Otherwise, the evaluation of the morphological variables proposed by the authors yielded promising results as a reliable sexing technique for individuals who died before puberty.

Obstetric dimensions of the female pelvis are less integrated than locomotor dimensions and show protective scaling patterns: Implications for the obstetrical dilemma

OBJECTIVES

The "obstetrical dilemma" hypothesis assumes that the modern human female pelvis serves two discrete functions: obstetrics and locomotion. We investigate whether these differing functions create observable patterns of morphological covariation and whether those patterns differ by height, weight, and age. This allows evaluation of evidence for canalization and phenotypic plasticity relevant to obstetric and locomotor function among a living female population.

METHODS

Landmarks (N = 86) were collected and inter-landmark distances were calculated (N = 36) on the pelvis and proximal femur of CT scans of living women aged 20 to 90 years (M = 93) receiving a routine CT scan. Partial least squares and relative SD of eigenvalues analyses were used to evaluate integration overall and within locomotor and obstetric modules, respectively. Ordinary Least Squared regression was used to evaluate scaling relationships between inter-landmark distances and height, weight, and age.

RESULTS

The obstetric pelvis was significantly less internally integrated than the locomotor pelvis. Many obstetric measurements were constrained in absolute terms relative to height; shorter women had relatively larger birth canal dimensions, and several key obstetric dimensions showed relative freedom from height. Lower weight women had some relatively larger obstetric and locomotor dimensions. Regarding age, younger women showed a few relatively larger outlet dimensions.

CONCLUSIONS

This study suggests that the obstetric pelvis and the locomotor pelvis function are morphologically distinct, with the obstetric pelvis showing relatively greater flexibility. These relationships between relative constraints support the hypothesis that the modern female pelvis shows evidence of both canalization and phenotypic plasticity in obstetric and locomotor structures.

The accuracy of 3D virtual bone models of the pelvis for morphological sex estimation

It is currently unknown whether morphological sex estimation traits are accurately portrayed on virtual bone models, and this hampers the use of virtual bone models as an alternative source of contemporary skeletal reference data. This study determines whether commonly used morphological sex estimation traits can be accurately scored on virtual 3D pelvic bone elements. Twenty-seven intact cadavers from the body donation program of the Amsterdam UMC, University of Amsterdam, were CT scanned; this data was used to produce virtual bone models. Thereafter, the dry bones were obtained. Three traits by Klales (2012) and five traits from the Workshop of European Anthropologists (WEA) (1980) were scored on the virtual bone models and their dry skeletal counterparts. Intra- and inter-observer agreement and the agreement between the scores for each virtual bone model-dry bone pair were calculated using weighted Cohen’s kappa (K). For all Klales (2012) traits, intra- and inter-observer agreement was substantial to almost perfect for the virtual- and dry bones (K = 0.62–0.90). The agreement in scores in the virtual-dry bone pairs ranged from moderate to almost perfect (K = 0.58–0.82). For the WEA (1980) traits, intra-observer agreement was substantial to almost perfect (K = 0.64–0.91), but results were less unambiguous for inter-observer agreement (K = 0.24–0.88). Comparison of the scores between the virtual bone models and the dry bones yielded kappa values of 0.42–0.87. On one hand, clinical CT data is a promising source for contemporary forensic anthropological reference data, but the interchangeability of forensic anthropological methods between virtual bone models and dry skeletal elements needs to be tested further.

Dimensions around the nutrient foramina of the tibia and fibula in the estimation of sex

Sex estimation from skeletal remains is one of the key components in establishing a biological profile and consequent identification of an individual in a forensic and medico-legal practice. The use of dimensions around the nutrient foramen in instances where long bones may be fragmented and damaged is of benefit due to the fact that the nutrient foramen is easily identifiable and may be preserved on the shaft of long bones. This study is an investigation of the usefulness of various measurements around the nutrient foramen of the tibia and fibula of South Africans in an attempt to develop osteometric standards for sex estimation. The sample included 206 tibiae and 204 fibulae of South African Africans (SAA) and South African whites (SAW) procured from the Raymond A. Dart Collection of Human Skeletons based at the University of the Witwatersrand. Sex was correctly classified for the tibia with an accuracy ranging between 79-82% in SAA and 84-88% in SAW, with the circumference at the level of the nutrient foramen as the single best predictor of sex in both populations. An accuracy ranging from 69 to 74% in SAA and 70-77% in SAW was observed for the combined measurements on the fibula. The current study confirms the usefulness of measurements around the nutrient foramen of the tibia in the assignment of sex. However functions of the fibula generally performed poorly and should be used with caution.

Three-dimensionally derived interlandmark distances for sex estimation in intact and fragmentary crania

The skull is the element most frequently presented to forensic anthropologists for analysis yet weathering, corpse maiming, and scavenger activity often result in damage and fragmentation. This fragmentation results in a reduction in the number of traditional calliper derived measurements that can be obtained and subjected to discriminant based analyses for sex estimation. In this investigation, we employed three-dimensional geometric morphometric methods to derive novel interlandmark distance measures across six regions of the cranium including the basicranium, basipalate, zygoma, orbits and the cranium globally to create functions to discriminate sex with high efficacy, even in the event of fragmentation. Forty-five homologous landmarks were digitised across each of 227 (114 males and 113 females) South African crania of European descent (white) sampled from the Raymond A Dart Collection of Human Skeletons, housed in the School of Anatomical Sciences, University of the Witwatersrand, South Africa. A total of 990 interlandmark distances (ILDs) were mathematically derived using Pythagorean geometry. These ILDs were then filtered by region and subjected to both direct and stepwise discriminant function analyses. Discriminant equations where derived for each region and achieved the following average cross-validated sex estimation accuracies: basicranium-74%; basipalate-80.2%; zygomatic-82.4; orbits-71.8%; nasomaxilla-83.7%; global cranium-88.2%. A large number of the ILDs used to derive the discriminant functions are novel, demonstrating the efficacy of geometric morphometric methods and illustrating the need to reassess old methods of data collection using modern methods to determine whether they best capture biological differences. The results of this study provide an invaluable contribution to forensic anthropology in South Africa as it provides an accurate, practical means of assessing sex using fragmentary material that may otherwise have been disregarded. These will undeniable aid in accurate sex estimation and ultimately, victim identification.

Pelvic Inlet Shape Is Not as Dimorphic as Previously Suggested

It is well known that there are significant differences in the pelves of males and females due, in part, to differing constraints. The male and female pelves must be suitable for upright posture and locomotion, but the female pelvis must also be suitable for reproduction. These differing requirements lead to differences in the shape and size of various pelvic dimensions. These differences are reflected in the pelvic inlet, midplane, and outlet. Current research has documented dimorphisms in the posterior and anterior spaces in all three of these planes. One measure however, that is calculated from the relationship between the length of the anterior-posterior diameter (APD) and the transverse diameter (TD) of the inlet, is not as dimorphic as previously suggested. This computed value is used to describe four main categories of inlet shape: android, gynecoid, anthropoid, and platypelloid. Current textbooks in anatomy and midwifery describe these forms and identify the typical male inlet shape as android and the typical female inlet shape as gynecoid. In this study, however, using skeletonized pelves of 378 adult individuals from three identified skeletal collections, the most common inlet shape for both males and females was android. In addition, when examining shape as a continuous variable, inlet shape is not sexually dimorphic in two of the three populations examined in this study. Based on the results of this study, the inlet shape for males and females is less dimorphic than previously thought, and we need to discontinue using pelvic categories to describe typical inlet shape. Anat Rec, 300:706-715, 2017. © 2017 Wiley Periodicals, Inc.

Ethnic differences in the levator hiatus and pelvic organ descent: a prospective observational study

OBJECTIVE

To date, most studies on functional anatomy of the pelvic floor have focused on Caucasian women. There is scant information on this topic involving other ethnic groups. The aim of this study was to investigate levator hiatal area and pelvic organ descent in three racially diverse ethnic groups of healthy nulliparous South Asian, Caucasian and black South African women, using three/four-dimensional (3D/4D) transperineal ultrasound (TPS).

METHODS

Nulliparous women aged 18-40 years from three different ethnic groups were recruited for this prospective observational study between June 2012 and April 2015. After informed consent and clinical examination of the pelvic floor, all patients underwent a 3D/4D-TPS examination. Ultrasound volumes were captured at rest, on maximum pelvic floor muscle contraction (PFMC) and on maximal Valsalva maneuver. Analyses of variance and covariance were performed to compare the three ethnic groups, and a post-hoc Bonferroni pairwise test was applied.

RESULTS

A total of 207 nulliparous women were recruited, comprising 41 South Asian, 69 Caucasian and 97 black women. After controlling for age and body mass index, all measurements of mean levator hiatal area at rest, on PFMC and on Valsalva were higher in black women (all P < 0.0001). Post-hoc Bonferroni pairwise comparison revealed that black women had greater pelvic organ descent and levator hiatal area compared with South Asian and Caucasian women (P < 0.0001).

CONCLUSION

This comparative study indicates that there are significant differences in levator hiatal area and pelvic organ mobility between Caucasian, South Asian and black ethnic groups. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Elliptical Fourier analysis: fundamentals, applications, and value for forensic anthropology

The numerical description of skeletal morphology enables forensic anthropologists to conduct objective, reproducible, and structured tests, with the added capability of verifying morphoscopic-based analyses. One technique that permits comprehensive quantification of outline shape is elliptical Fourier analysis. This curve fitting technique allows a form's outline to be approximated via the sum of multiple sine and cosine waves, permitting the profile perimeter of an object to be described in a dense (continuous) manner at a user-defined level of precision. A large amount of shape information (the entire perimeter) can thereby be collected in contrast to other methods relying on sparsely located landmarks where information falling in between the landmarks fails to be acquired. First published in 1982, elliptical Fourier analysis employment in forensic anthropology from 2000 onwards reflects a slow uptake despite large computing power that makes its calculations easy to conduct. Without hurdles arising from calculation speed or quantity, the slow uptake may partly reside with the underlying mathematics that on first glance is extensive and potentially intimidating. In this paper, we aim to bridge this gap by pictorially illustrating how elliptical Fourier harmonics work in a simple step-by-step visual fashion to facilitate universal understanding and as geared towards increased use in forensic anthropology. We additionally provide a short review of the method's utility for osteology, a summary of past uses in forensic anthropology, and software options for calculations that largely save the user the trouble of coding customized routines.

The geometrical precision of virtual bone models derived from clinical computed tomography data for forensic anthropology

Almost all European countries lack contemporary skeletal collections for the development and validation of forensic anthropological methods. Furthermore, legal, ethical and practical considerations hinder the development of skeletal collections. A virtual skeletal database derived from clinical computed tomography (CT) scans provides a potential solution. However, clinical CT scans are typically generated with varying settings. This study investigates the effects of image segmentation and varying imaging conditions on the precision of virtual modelled pelves. An adult human cadaver was scanned using varying imaging conditions, such as scanner type and standard patient scanning protocol, slice thickness and exposure level. The pelvis was segmented from the various CT images resulting in virtually modelled pelves. The precision of the virtual modelling was determined per polygon mesh point. The fraction of mesh points resulting in point-to-point distance variations of 2 mm or less (95% confidence interval (CI)) was reported. Colour mapping was used to visualise modelling variability. At almost all (>97%) locations across the pelvis, the point-to-point distance variation is less than 2 mm (CI = 95%). In >91% of the locations, the point-to-point distance variation was less than 1 mm (CI = 95%). This indicates that the geometric variability of the virtual pelvis as a result of segmentation and imaging conditions rarely exceeds the generally accepted linear error of 2 mm. Colour mapping shows that areas with large variability are predominantly joint surfaces. Therefore, results indicate that segmented bone elements from patient-derived CT scans are a sufficiently precise source for creating a virtual skeletal database.

A sequential comparison of postoperative voiding function between two different transobturator sling procedures

INTRODUCTION

We evaluated sequential postoperative voiding function of two types of sling procedures (Monarc^® and ALIGN^®) in patients with stress urinary incontinence.

METHODS

Ninety-one women diagnosed with urodynamic stress incontinence were randomly assigned to the study. All enrolled patients underwent Monarc or ALIGN procedure. They were postoperatively evaluated at one day, one week, one month, three months, 12 months, and 24 months. The voiding function was evaluated with uroflowmetry and post-void residual urine. Patients were asked if voiding had changed after surgery and had to complete the incontinence quality of life scale (I-QoL) questionnaire at 12 months.

RESULTS

The Monarc (n=47) and ALIGN (n=44) groups had similar demographic characteristics. The maximal flow rate (Qmax) was significantly decreased on the first day after surgery and gradually increased during the following weeks. Comparing the two groups at one week, the ALIGN group had a significantly decreased Qmax than the Monarc group (17.6 ± 5.2 vs. 20.7 ± 5.0; p=0.004). However, at one, three, 12, and 24 months, there were no significant differences between the two groups.

CONCLUSIONS

This study demonstrated that an absorbable tensioning suture in the Monarc mesh could increase Qmax compared to ALIGN at one week after surgery. An absorbable tensioning suture may reduce the risk of an early postoperative voiding dysfunction compared to other meshes that do not have this.

Accuracy of mandibular measurements of sexual dimorphism using stabilizer equipment

The objective of this investigation was to compare the accuracy of mandibular measurements using a stabilizer (MS) with gold standard computed tomography (GS) images. Sixty mandibles were studied. Werth TomoScope HV Compact® was used to obtain CT images (GS), and the MS was also used. Analysis of the CT scans was performed using the VG Studio Max software® (Volume Graphics GmbH, Heidelberg, Germany), and MS was used after the proper positioning of the mandible. Descriptive and paired t test measures were used, and a ROC curve was calculated, as well as sensibility and specificity. MedCalc and STATA 13.0® were used (95% level of significance). Bicondylar breadth, bicoronoid breadth and minimum ramus breadth reached the highest concordance correlation coefficients at 0.99 (0.99-1.00), 0.99 (0.99-1.00) and 1.00 (0.99-1.00), respectively. Comparing observers with GS, the lowest accuracy was noted for the maximum mandibular length [0.59 (0.45-0.69), 0.64 (0.51-0.74)], the breadth of the right (0.14 (0.04-0.23), 0.14 (0.004-0.24)) and left mandibular body [0.14 (0.03-0.24), 0.16 (0.05-0.26)], and the right [0.58 (0.45-0.69), 0.63 (0.51-0.73) and left (0.59 (0.45-0.70), 0.59 (0.46-0.69)] mandibular angle. Various measurements exhibited good sensibility for males using MS: maximum mandibular length (78.12), bicondylar breadth (78.12), left mandibular notch breadth (84.37), and the left height of the mandibular body at the mental foramen (75.00). High specificity in discriminating females was observed for the left maximal ramus height (85.19), mandibular length (85.71), bicoronoid breadth (96.43), right height of the mandibular body at the mental foramen (82.19), bimental breadth (78.57), breadth right (92.86) and left (96.43) mandibular body, minimum ramus breadth (89.29), and left mandibular angle (85.71). MS was able to discriminate sexual dimorphism.

Assessment of the variability in the dimensions of the intact pelvic canal in South Africans: A pilot study

Cephalopelvic disproportion is common among Africans and is a major cause of maternal and perinatal mortality and morbidity. As the dimensions of the pelvis may vary between populations and according to stature and age, they need to be considered during childbirth and also in the planning and performance of pelvic and perineal procedures. The aim of this study was to assess the possible variations in the dimensions of the intact pelvic canal in South Africans and their implications. Eighty intact cadaver pelves, belonging to 40 white South Africans (20 males and 20 females) and 40 black South Africans (20 males and 20 females) were used for both metric and geometric morphometric analyses. Pelvic inlet shapes did not differ significantly between groups but pelvic inlet and midpelvic dimensions were the greatest in white South Africans and females. The pubic symphyseal length was the greatest in white males and the smallest in black females, resulting in a smaller pelvic cavity anteriorly than for white females. Pelvic outlet shapes varied significantly between sexes in white South Africans and between white and black males. Females presented with the greatest dimensions. Black South African females presented with an elongated anteroposterior outlet diameter. Certain transverse pelvic diameters correlated positively with age in white males and with height in females. In planning childbirth options, the smaller pelvic inlet of black females and stature-dependent diameters should be considered. Pelvic and perineal surgery may be technically more challenging because of smaller pelvic dimensions in black South Africans, especially in males.

A review of sex estimation techniques during examination of skeletal remains in forensic anthropology casework

Sex estimation is considered as one of the essential parameters in forensic anthropology casework, and requires foremost consideration in the examination of skeletal remains. Forensic anthropologists frequently employ morphologic and metric methods for sex estimation of human remains. These methods are still very imperative in identification process in spite of the advent and accomplishment of molecular techniques. A constant boost in the use of imaging techniques in forensic anthropology research has facilitated to derive as well as revise the available population data. These methods however, are less reliable owing to high variance and indistinct landmark details. The present review discusses the reliability and reproducibility of various analytical approaches; morphological, metric, molecular and radiographic methods in sex estimation of skeletal remains. Numerous studies have shown a higher reliability and reproducibility of measurements taken directly on the bones and hence, such direct methods of sex estimation are considered to be more reliable than the other methods. Geometric morphometric (GM) method and Diagnose Sexuelle Probabiliste (DSP) method are emerging as valid methods and widely used techniques in forensic anthropology in terms of accuracy and reliability. Besides, the newer 3D methods are shown to exhibit specific sexual dimorphism patterns not readily revealed by traditional methods. Development of newer and better methodologies for sex estimation as well as re-evaluation of the existing ones will continue in the endeavour of forensic researchers for more accurate results.

Evaluation of demographic factors affecting predictability of the sacro-femoral-pubic angle in healthy adolescents

The objectives of the present study are to evaluate the correlation between pelvic tilt (PT) and the sacro-femoral-pubic (SFP) angle in Asian healthy adolescents, to provide the normal value of SFP angle as reference data in Asian adolescents, and to clarify whether the predictability of PT could be affected by gender and ontogenesis. In all, 100 girls with a mean age of 12.66 years (range 8-18 years) and 70 boys with a mean age of 13.35 years (range 8-18 years) were recruited in this retrospective study. SFP angles and PT were obtained on long-cassette standing upright radiographs. The subjects were grouped based on age. Independent-sample t-tests were performed to compare age, SFP angle, and PT between genders. In all age groups, the relationship between SFP angle and PT was analyzed by Pearson's correlation analysis and linear regression analysis, respectively. Reliability analysis showed high intra- and inter-observer agreements in PT and SFP, with an intra-class correlation coefficient (ICC) > 0.8. SFP angle averaged 71.64° ± 4.91 in all the normal subjects, of which the mean PT was 72.03°± 4.94 in the female group and 71.09°± 4.83 in the male group. SFP and PT were strongly correlated in all the age groups according to Pearson's correlation analysis. The overall coefficient was 0.679 in girls and 0.584 in boys. The present study is the first to describe the normal value of SFP angle in healthy Asian adolescents to serve as a reference data. In all age groups, SFP angles can be used to predict PT when lateral radiographs do not permit assessment of PT. The predictability of SFP angle for PT was not affected by gender or maturation status.

The ratio of femoral head diameter to pelvic height in the normal hips of a Chinese population

OBJECTIVE

The aim of this study was to determine whether the ratio between the femoral head diameter and pelvic height in a Chinese population is the same as that found in Westerners.

MATERIALS AND METHODS

Standard pelvic radiography was performed on a group of 187 Chinese adult subjects consisting of 81 males and 106 females with a mean age of 40 years (21-68 years). Femoral head diameter (vertical distance from the femoral head-neck junction to the highest point of the femoral head) and pelvic height (vertical distance from the highest point of the iliac crest to the edge of the ischial tuberosities) were measured.

RESULTS

There were significant differences between males and females (p < 0.001), and between persons of high height versus low height (p = 0.011) and medium height (p = 0.039). There were no significant differences between persons of different age (p = 0.244), body mass index (p = 0.091), or between persons of low- and medium-height groups (p = 0.69). The overall mean ratio between the femoral head diameter and pelvic height was 0.215 (0.173-0.249) with a 95 % CI = 0.214-0.217. The mean ratios in males and females were 0.221 (0.194-0.249) and 0.211 (0.173-0.238), respectively.

CONCLUSION

The mean ratio in Chinese population was similar to the reported ratio in a western population (about 1:5). We suggest that Chinese surgeons may be able to use the Crowe classification to classify patients with hip dysplasia.

Radiographic examination of the greater sciatic notch in determining the sex among Iranian people

The distinctive morphology of the human innominate bone (os coxae) and its clear sexual dimorphism make it of interest from anatomical, anthropological and forensic points of view. The features of the greater sciatic notch of the coxae are characteristic and are commonly used to determine sex in unknown individuals. In this study, several measurements of the greater sciatic notch, e.g. width (AB), depth (OC) and width of the posterior segment (OB) were taken and indices I and II were calculated in 64 adult (32 men and 32 women) and side (right: left) coxae radiography (A-P view). Results indicated that out of all the parameters studied, width of the notch (right and left) (P < 0.001), posterior segment width (right and left) (P < 0.001), right (P = 0.036) and left (P = 0.008) index II of notch were found to be significantly greater in women as compared with men. Discriminant function analysis showed that the accuracy of sex determination varied from 100% in the men and 40% in the women groups to 70% for the total group. These results can be used as an aid to the identification of human skeletal remains in Iranian people.

Comparison of methods to determine sex by evaluating the greater sciatic notch: Visual, angular and geometric morphometrics

Sex estimation is the first step for biological profile reconstruction of an unknown skeleton (archaeological or contemporary) and consequently for positive identification of skeletal remains recovered from forensic settings. Several tools have been developed using different osseous structures. With the intention to provide an objective method comparison, we reported the analysis of three different methods (visual, metric and geometric morphometrics) for sex assessment of the greater sciatic notch. One hundred and thirty pelvic bones (45.4% females and 54.6% males) from the National Autonomous University of Mexico Skeletal Collection pertaining to the contemporary Mexican population were analyzed. We used the ROC-analysis to test between desired false positive thresholds (1-specificity) and expected true positive rates (sensitivity) in order to predict the best approach to sex assessment. The comparison of the area under the ROC-curves shows significant differences among visual and metric methods. At the same time, the analysis suggested that higher morphological variation among the sexes is independent of the methodological approach. The results indicate that the metric (angle), with a high percent of indeterminate cases (34.6%), and visual, with 26.2% of the cases allocated as intermediate cases, were poorly accurate; we cannot recommend these techniques for sexing an unknown specimen. On the other hand, the geometric morphometrics approach improves sex estimation in 82.3% of correctly classified individuals with more than 95% of posterior probability. In addition to the method comparison, the major sexual variation of the greater sciatic notch was determined to be located on its posterior border.

Human coxal bone sexual dimorphism and multislice computed tomography: geometric morphometric analysis of 65 adults

The authors studied sexually dimorphic differences in coxal shape using geometric morphometric analysis of 15 osteometric landmarks recorded by multislice computed tomography (MSCT), based on three-dimensional reconstructions of 65 Caucasian adults. Geometric morphometric analysis, principal component analysis, canonical variates analysis, and other discriminant analysis (Goodall's F-test and Mahalanobis distance) were performed for the three separate bones of the left innominate (pubis, ilium, and ischium), the modified pubis (pubis and ischiopubic ramus), the modified ilium (ilium and ischial spine), three bone complexes (ischiopubic, iliopubic, and ilio-ischial), and the complete innominate. A cross-validation test was also performed. All areas studied were dimorphic, but results for sexual dimorphism in decreasing order were as follows: the modified pubis, followed by the ischiopubic complex, the iliopubic complex and the complete innominate, the pubis, the modified ilium, the ilio-ischial complex, the ilium, and finally the ischium. These results show the potential of this approach for future anthropological research.

Sacro-femoral-pubic angle: a coronal parameter to estimate pelvic tilt

INTRODUCTION

Pelvic tilt is an established measure of position which has been tied to sagittal plane spinal deformity. Increased tilt is noted in the setting of the aging spine and sagittal malalignment syndromes such as flatback (compensatory mechanism). However, the femoral heads are often poorly visualized on sagittal films of scoliosis series in adults, limiting the ability to determine pelvic incidence and tilt. There is a need to establish a coronal plane (better visualization) pelvic parameter which correlates closely with pelvic tilt.

METHODS

This is a retrospective review of 71 adult patients (47 females and 24 males) with full-length standing spine radiographs. Visualization of all spinal and pelvic landmarks was available coronally and sagittally (including pelvis and acetabuli). Pelvic tilt was calculated through validated digital analysis software (SpineView(®)). A new parameter, the sacro-femoral-pubic angle (midpoint of S1 endplate to centroid of acetabuli to superior border of the pubic symphysis) was analyzed for correlation (and predictive ability) with sagittal pelvic tilt.

RESULTS

The sacro-femoral-pubic angle (SFP angle) was highly correlated to PT, and according to this analysis, pelvic tilt could be estimated by the formula: PT = 75 - (SFP angle). A Pearson's correlation coefficient of 0.74 (p < 0.005) and predictive ability of 76% accuracy was obtained (±7.5°). The correlation and predictive ability was greater for males compared to females (male: r = 0.87 and predictive model = 93%; female: r = 0.67 and predictive model = 67%).

CONCLUSION

The pelvic tilt is an essential measure in the context of radiographic evaluation of spinal deformity and malalignment. Given the routinely excellent visibility of coronal films this study established the SFP as a coronal parameter which can reliably estimate pelvic tilt. The high correlation and predictive ability of the SFP angle should prompt further study and clinical application when lateral radiographs do not permit assessment of pelvic parameters.

Oval in males and triangular in females? A quantitative evaluation of sexual dimorphism in the human obturator foramen

Among the numerous pelvic traits presenting sex differences, the obturator foramen is classically described as being oval in males and triangular in females. However, no demonstrations or detailed studies seem available in the literature. The purpose of this work was to study quantitatively this trait using Fourier analysis, because this methodological approach is particularly well adapted for discrimination between different simple shapes. Using this approach, an outline can be characterized by a series of harmonics (1 to n), each defined by two Fourier descriptors: amplitude (C(n)), describing the relative importance of the harmonic contribution to the original shape, and phase (Phi(n)), representing the orientation of the harmonic contribution. The material consisted of 104 three-dimensional CT reconstructions of adult pelves (52 males and 52 females). After size normalization, the outlines of the 104 left obturator foramens were studied. Significant differences were demonstrated with, in total, 84.6% of individuals presenting a correct inferred sex. The most discriminating descriptors were the phase of the second harmonic (C(2),) related to the oval (or elliptic) aspect and thus the elongation of the shape, and the amplitude of the third harmonic (Phi(3)), describing the triangularity of the shape. Because the trend for an outline to be more or less oval or triangular is difficult to visually assess and because there is an infinite number of transitional shapes, only a precise quantitative approach such as Fourier analysis allows for unambiguous characterization and statistical analysis.

Geometric morphometric approach to sex estimation of human pelvis

Sex estimation of skeletal remains is an important issue in both forensics and bioarchaeology. The chance of attaining a high level of accuracy regarding sex allocations is related to the skeletal component analyzed and the ability of the techniques employed to describe shape and size differences among the sexes. Current opinion regards the hip bone as the most reliable sex indicator because it is the most dimorphic bone, particularly in adult individuals. The aim of this study was therefore to analyze the greater sciatic notch and the ischiopubic complex morphology by employing geometric morphometric techniques, based on semilandmark and multivariate statistical methods, in order to develop a reliable and accurate technique for adult sex estimation. The sample analyzed consisted of 121 adult left hip bones randomly selected from the collection of documented skeletons housed at the Museu Antropologico de Coimbra. Morphometric analysis was based on coordinates of landmarks and semilandmarks of the ilium and ischiopubic regions that were digitized on 2D photographic images. Discriminant analysis with leave-one-out cross-validation and k-means clustering of shape and shape-size variables were used in order to classify individuals by sex. For the greater sciatic notch, average accuracy of 90.9% was achieved with both multivariate analyses based on shape variables. For the ischiopubic complex, the values obtained with shape variables were 93.4% and 90.1% for discriminant and k-means, respectively. Females were misclassified more frequently than males, especially for the ischiopubic complex. When multivariate statistical analyses were performed using shape-size variables, the percentages of correct classifications were lower than those obtained with shape variables. We conclude that the use of geometric morphometrics and multivariate statistics is a reliable method to quantify pelvic shape differences between the sexes and could be applied to discriminate between females and males.