Comparing morphological (os coxae) and metric (long bone length) sex estimation methods in archaeological collections.

Objectives: The aim of this study is to evaluate the internal consistency of sex estimation using metric (long bone length) and morphological (os coxae) methodologies from different bones and across different archaeological populations from different regions. Materials and Methods: Sex was estimated using characteristics of the pelvis and compared with sex estimations using long bone length. Portuguese (659 females; 906 males) and English (141 females; 277 males) archaeological collections were analysed in this study. A set of long bone length functions were developed using one of the archaeological collections (531 females; 600 males) and its coincidence with sex estimated from the pelvis was compared to the coincidence between the pelvis and long bone length sex estimations using functions developed from contemporary collections. Intra- and inter-observer errors were calculated, as well as the sexual dimorphism index for each bone and osteological collection. Results: The accuracy of the developed functions and the other methods tested is highly variable, ranging between 25 and 100%. The accuracy of the standard forensic methods varied between collections and analysed bones. Discussion: This study reinforces that long bone length is highly population-specific, even between samples of close chronology and geography. Metric methods are good options to strengthen the sex estimations, but they need to be carefully chosen and always report the estimated probability of being male or female in either forensic or archaeological analysis.

DSP2 for sex determination of miscegenated contemporary hip bones.

The bones of the human pelvis are used in sexual diagnosis generating a high level of accuracy for this type of identification. Morphological and/or morphometric methods are used in the identification of sex. Sexual dimorphism may be affected by ethnic differences in the population. One of the methods for determining sex using hip bone is the 'Diagnose Sexuelle Probabiliste (DSP)' or Probabilistic Sexual Diagnosis (DSP) method. The method presents a new version (Probabilistic Sexual Diagnosis v.2-DSP2) more advisable to be used because it has a more up-to-date database. The objective of this study is to investigate the applicability of the DSP2 method in a population in the Northeast region of Brazil. We used 128 hip bones, 50 female and 78 males, aged between 17 and 101 years, belonging to the Laboratory of Human Identification and Forensic Osteology of the University Federal Government of Pernambuco. The research was conducted between 2019 and 2020 and approved by the Research Ethics Committee of the Federal University of Pernambuco no. 43228015.0.0000.5208. The probability equal to or greater than 0.95 was used as the limit for the determination of sex, and the results were compared with the actual sex of each bone. In the Brazilian collection study, it was observed that the percentage of sex estimation provided by the DSP2 tool using all reference samples was 71.09%, and accuracy was 64.06%. In the analysis of the gender estimate, 82.0% and 78% were obtained for females and males, respectively. Regarding accuracy, it was 64.10% and 55.13% for females and males, respectively. In the contemporary osteological collection of the Northeast region of Brazil, which presents immigrant peoples, we obtained a high index of assertiveness in the DSP2 method. The study concluded that the DSP2 method is important for determining the sex of human skeletons in a miscegenated population.

Beyond sex, gender, and other dilemmas: Human pelvic morphology from an integrative context.

Recent research on the pelvis has clarified the flexibility of pelvic bones to manage nearly infinite possibilities in terms of selection and drift, while still maintaining excellent bipedalism. Despite this work, and the studies outlining the diversity of pelvic morphology across the hominin lineage, conversations continue to be stymied by distractions related to purported trade-offs that the different functions the pelvis must either allow for (e.g., parturition) or directly perform (e.g., attachment sites of muscles). Here we show that tight constraints on morphology are not evident in the pelvic variation of multiple human populations. We thus provide further evidence that human pelves are not geometrically similar and that pelvic morphology successfully balances the intersection of population history, active selective, and drift.

Pelvic shape change in adult Japanese macaques and implications for childbirth at old age.

Pelvic morphology exhibits a particular sexual dimorphism in humans, which reflects obstetrical constraints due to the tight fit between neonates and mothers. Huseynov et al. [Proc. Natl. Acad. Sci. U.S.A. 113, 5227-5232 (2016)] showed that in humans, pelvic sexual dimorphism is greatest around the age of highest fertility, and it becomes less marked in association with menopause in females. They proposed that this reflects changes of obstetrical versus locomotor functional demands in females. It remains unknown whether such developmental adjustment of the pelvic morphology is unique to humans. Macaques exhibit human-like cephalopelvic proportions, but they lack menopause and usually maintain fertility throughout adulthood. Here, we track pelvic development in Japanese macaques from neonate to advanced ages using computed tomography-based data. We show that female pelvic morphology changes throughout adult life, reaching the obstetrically most favorable shape at advanced ages rather than around primiparity. We hypothesize that pelvic morphology in Japanese macaques is developmentally adjusted to childbirth at advanced ages, where obstetrical risks are potentially higher than at younger ages. Our data contribute to the growing evidence that the female primate pelvis changes its morphology during the whole lifespan, possibly adjusting for changing functional demands during adulthood.

Sexual dimorphism and ancestral variation in the pectoral and pelvic girdles of modern humans.

Discussions of the evolution of sexual dimorphism in torso shape and the pectoral region assume that this dimorphism exists independently of body size. We test this assumption in two human populations and further examine what is needed to understand sexual dimorphism in the pectoral region. Modern human males have broad shoulders and narrow hips relative to females, lending males a more triangular torso. The wider female pelvis is commonly attributed to obstetric pressures while the broader male pectoral girdle has been argued to be an adaptation that improves hunting or intrasexual competition. While sexual dimorphism in the pelvic girdle is known to exist after adjusting for body size across human populations, most studies of sexual dimorphism in the pectoral girdle have not adjusted the data to account for sexual size dimorphism or compared different ancestral groups. The aforementioned hypotheses explaining sexual dimorphism in the clavicle and scapula as products of natural selection are predicated on the untested assumption that sex differences do not scale with body size. This study tests this assumption by comparing various measurements of the pectoral girdle, the pelvic girdle, and six pectoral-pelvic indices of black and white South Africans of known sex and height to test whether the sexes and ancestral groups will differ in these values after adjusting for differences in body size. Comparisons of ancestral groups reveal that white South Africans have larger pectoral and pelvic dimensions than black South Africans, but that blacks have larger index values than whites. Regardless of differences in ancestry and body size, males have significantly broader pectoral regions as indicated by comparisons of both individual pectoral measurements and pectoral-pelvic indices. This pattern of sexual dimorphism is reversed in the pelvic region where females have larger skeletal elements. In addition to finding both absolute and relative differences in mean values for the pectoral and pelvic skeleton, females and males and blacks and whites differ in the scaling relationship of these traits, suggesting different allometric trajectories for these bones that may be explained by their distinct evolutionary functions, their adaptations to specific environments, or by changes in lengths due to age. These results suggest that sexual dimorphism in the pectoral region is not a product of scaling and that differences in this region reflect adaptive forces acting in unique ways on each sex, consistent with the assumptions of earlier evolutionary explanations.

Pelvic incidence significance relative to spinopelvic risk factors for total hip arthroplasty instability.

AIMS: Pelvic incidence (PI) is a position-independent spinopelvic parameter traditionally used by spinal surgeons to determine spinal alignment. Its relevance to the arthroplasty surgeon in assessing patient risk for total hip arthroplasty (THA) instability preoperatively is unclear. This study was undertaken to investigate the significance of PI relative to other spinopelvic parameter risk factors for instability to help guide its clinical application. METHODS: Retrospective analysis was performed of a multicentre THA database of 9,414 patients with preoperative imaging (dynamic spinopelvic radiographs and pelvic CT scans). Several spinopelvic parameter measurements were made by engineers using advanced software including sacral slope (SS), standing anterior pelvic plane tilt (APPT), spinopelvic tilt (SPT), lumbar lordosis (LL), and PI. Lumbar flexion (LF) was determined by change in LL between standing and flexed-seated lateral radiographs. Abnormal pelvic mobility was defined as ∆SPT ≥ 20° between standing and flexed-forward positions. Sagittal spinal deformity (SSD) was defined as PI-LL mismatch > 10°. RESULTS: PI showed a positive correlation with parameters of SS, SPT, and LL (r-value range 0.468 to 0.661). Patients with a higher PI value showed higher degrees of standing LL, likely as a compensatory measure to maintain sagittal spine balance. There was a positive correlation between LL and LF such that patients with less standing LL had decreased LF (r = 0.49). Similarly, there was a positive correlation between increased SSD and decreased LF (r = 0.54). PI in isolation did not show any significant correlation with lumbar (r = 0.04) or pelvic mobility (r = 0.02). The majority of patients (range 89.4% to 94.2%) had normal lumbar and pelvic mobility regardless of the PI value. CONCLUSION: The PI value alone is not indicative of either spinal or pelvic mobility, and thus in isolation may not be a risk factor for THA instability. Patients with SSD had higher rates of spinopelvic stiffness, which may be the mechanism by which PI relates to THA instability risk, but further clinical studies are required. Cite this article: Bone Joint J 2022;104-B(3):352-358.

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 comparative study of visual assessment between dry bone, 2-dimensional photograph, and deep learning methods in sex classification on the auricular area of the os coxae in a Thai population / Un estudio comparativo de la evaluación visual entre el hueso seco, la fotografía bidimensional y los métodos de aprendizaje profundo en la clasificación del sexo en el área auricular del hueso coxal en una población tailandesa

SUMMARY: Sex assessment is an important process in forensic identification. A pelvis is the best skeletal element for identifying sexes due to its sexually dimorphic morphology. This study aimed to compare the accuracy of the visual assessment in dry bones as well as 2D images and to test the accuracy of using a deep convolutional neural network (GoogLeNet) for increasing the performance of a sex determination tool in a Thai population. The total samples consisted of 250 left os coxa that were divided into 200 as a 'training' group (100 females, 100 males) and 50 as a 'test' group. In this study, we observed the auricular area, both hands-on and photographically, for visual assessment and classified the images using GoogLeNet. The intra-inter observer reliabilities were tested for each visual assessment method. Additionally, the validation and test accuracies were 85, 72 percent and 79.5, 60 percent, for dry bone and 2D image methods, respectively. The intra- and inter-observer reliabilities showed moderate agreement (Kappa = 0.54 - 0.67) for both visual assessments. The deep convolutional neural network method showed high accuracy for both validation and test sets (93.33 percent and 88 percent, respectively). Deep learning performed better in classifying sexes from auricular area images than other visual assessment methods. This study suggests that deep learning has advantages in terms of sex classification in Thai samples.

RESUMEN: La evaluación del sexo es un proceso importante en la identificación forense. La pelvis es el mejor elemento esquelético para identificar sexos debido a su morfología sexualmente dimórfica. Este estudio tuvo como objetivo comparar la precisión de la evaluación visual en huesos secos, así como imágenes 2D y probar la precisión del uso de una red neuronal convolucional profunda (GoogLeNet) para aumentar el rendimiento de una herramienta de determinación de sexo en una población tailandesa. Las muestras consistieron en 250 huesos coxales izquierdos, los que fueron dividi- das de la siguiente manera: 200 como un grupo de "entrenamiento" (100 mujeres, 100 hombres) y 50 como un grupo de "prueba". En este estudio, observamos el área auricular, tanto de forma práctica como fotográfica, para una evaluación visual y clasificamos las imágenes utilizando GoogLeNet. Se analizó la confiabilidad intra-interobservador para cada método de evaluación visual. Además, las precisiones de validación y prueba fueron del 85, 72 por ciento y 79,5, 60 por ciento, para los métodos de hueso seco y de imágenes 2D, respectivamente. Las confiabilidades intra e interobservador mostraron un acuerdo moderado (Kappa = 0.54 - 0.67) para ambas evaluaciones visuales. El método de red neuronal convolucional profunda mostró una alta precisión tanto para la validación como para los conjuntos de prueba (93,33 por ciento y 88 por ciento, respectivamente). El aprendizaje se desempeñó mejor en la clasificación de sexos a partir de imágenes del área auricular que otros métodos de evaluación visual. Este estudio sugiere que el aprendizaje profundo tiene ventajas en términos de clasificación por sexo en muestras tailandesas.

CT-based evaluation of the acetabulum for age estimation in an Indian population.

Age estimation constitutes an important aspect of forensic research, investigation and human identification. For the purpose of age estimation, various markers within the skeletal framework are employed. Degenerative morphological changes in the skeleton can be used for age estimation in adults. Amongst the various bones, age-progressive changes in the innominate bone are of particular significance in age estimation. Within the pelvis, the acetabulum presents as a durable and well-preserved evidence, characteristic manifestations of which can be employed for age estimation. The present study aimed at a CT-based evaluation of acetabular changes for the purpose of age estimation in an Indian population. CT images of 250 individuals aged 10-88 years were scrutinized according to the features defined in the Calce method of acetabular age estimation. Scores were allotted to the various features and a cumulative score was calculated. No significant bilateral and sex differences were observed. Significant correlation was obtained between the scores for these defined characteristics and the chronological age of individuals. Population-specific regression models were generated for age estimation. The scoring method devised in the present research requires further validation as it represents a new tool for age estimation in medico-legal cases.

Pelvic incidence is not associated with the development of hip osteoarthritis.

AIMS: Pelvic incidence (PI) is considered an important anatomical parameter for determining the sagittal balance of the spine. The contribution of an abnormal PI to hip osteoarthritis (OA) remains controversial. In this study, we aimed to investigate the relationship between PI and hip OA, and the difference in PI between hip OA without anatomical abnormalities (primary OA) and hip OA with developmental dysplasia of the hip (DDH-OA). METHODS: In this study, 100 patients each of primary OA, DDH-OA, and control subjects with no history of hip disease were included. CT images were used to measure PI, sagittal femoral head coverage, α angle, and acetabular anteversion. PI was also subdivided into three categories: high PI (larger than 64.0°), medium PI (42.0° to 64.0°), and low PI (less than 42.0°). The anterior centre edge angles, posterior centre edge angles, and total sagittal femoral head coverage were measured. The correlations between PI and sagittal femoral head coverage, α angle, and acetabular anteversion were examined. RESULTS: No significant difference in PI was observed between the three groups. There was no significant difference between the groups in terms of the category distribution of PI. The DDH-OA group had lower mean sagittal femoral head coverage than the other groups. There were no significant correlations between PI and other anatomical factors, including sagittal femoral head coverage, α angle, and acetabular anteversion. CONCLUSION: No associations were found between mean PI values or PI categories and hip OA. Furthermore, there was no difference in PI between patients with primary OA and DDH-OA. From our evaluation, we found no evidence of PI being an independent factor associated with the development of hip OA. Cite this article: Bone Joint J 2021;103-B(11):1656-1661.

Synchronous imaging of pelvic geometry and muscle morphometry: a pilot study of pelvic retroversion using upright MRI.

This study investigated feasibility of imaging lumbopelvic musculature and geometry in tandem using upright magnetic resonance imaging (MRI) in asymptomatic adults, and explored the effect of pelvic retroversion on lumbopelvic musculature and geometry. Six asymptomatic volunteers were imaged (0.5 T upright MRI) in 4 postures: standing, standing pelvic retroversion, standing 30° flexion, and supine. Measures included muscle morphometry [cross-sectional area (CSA), circularity, radius, and angle] of the gluteus and iliopsoas, and pelvic geometry [pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), L3-S1 lumbar lordosis (LL)] L3-coccyx. With four volunteers repeating postures, and three raters assessing repeatability, there was generally good repeatability [ICC(3,1) 0.80-0.97]. Retroversion had level dependent effects on muscle measures, for example gluteus CSA and circularity increased (up to 22%). Retroversion increased PT, decreased SS, and decreased L3-S1 LL, but did not affect PI. Gluteus CSA and circularity also had level-specific correlations with PT, SS, and L3-S1 LL. Overall, upright MRI of the lumbopelvic musculature is feasible with good reproducibility, and the morphometry of the involved muscles significantly changes with posture. This finding has the potential to be used for clinical consideration in designing and performing future studies with greater number of healthy subjects and patients.

Reproducibility and Accuracy of Pelvic Tilt in Predicting the Difference Between Pelvic Incidence and Lumbar Lordosis Value.

OBJECTIVE: We investigated the pelvic morphologic factors that determine the degree of pelvic incidence (PI)-lumbar lordosis (LL) mismatch. METHODS: Overall, 306 patients were included. The regional and global sagittal parameters were measured. Linear regression analyses were performed for 4 pelvic parameters and PI-LL mismatch. E1 and E2 were defined as linear regression equations between pelvic tilt (PT) and PI-LL mismatch and PI and PI-LL mismatch, respectively. The patients were categorized by cluster analysis using the hierarchal method for the 4 pelvic parameters. RESULTS: E1 and E2 showed statistical significance; however, the coefficient of determination of E1 was higher than that of E2 (R2 = 0.675 vs. 0.238; P < 0.01). Sex, LL, E1, and E2 showed significant differences in the regional parameters. The T1 pelvic angle (TPA), spinosacral angle (SSA), and incidence angle of inflection points (IAIPs) showed significant differences in global parameters (P < 0.01). The IAIPs and TPA were low in the anteverted pelvis group and high in the retroverted pelvis group (P < 0.001). The SSA was low in the small pelvis group and high in the large pelvis group (P < 0.001). The proportion of women in the large pelvis group (93%) was significantly higher than that in the other groups (P < 0.01). CONCLUSIONS: The individual differences between the PI and LL values can be more accurately determined using the individual PT, and the optimal PT amount will differ depending on the pelvis shape. The increase in the TPA and IAIPs corresponded to the PT, and the SSA increased in accordance with the pelvic size.

Sex estimation from the greater sciatic notch: a comparison of classical statistical models and machine learning algorithms.

The greater sciatic notch (GSN) is a useful element for sex estimation because it is quite resistant to damage, and thus it can often be assessed even in poorly preserved skeletons. This study aimed to develop statistical models for sex estimation based on visual and metric analyses of the GSN, and additional variables linked to the GSN. A total of 60 left coxal bones (30 males and 30 females) were analysed. Fifteen variables were measured, and one was a morphologic variable. These 16 variables were used for the comparison of six statistical models: linear discriminant analysis (LDA), regularized discriminant analysis (RDA), penalized logistic regression (PLR) and flexible discriminant analysis (FDA), and two machine learning algorithms, support vector machine (SVM) and artificial neural network (ANN). The statistical models were built in two steps: firstly, only with the GSN variables (group 1), and secondly, with the whole variables (group 2), in order to see if the models including all the variables performed better. The overall accuracy of the models was very close, ranging from 0.92 to 0.97 using specific GSN variables. When additional variables starting from the deepest point of GSN are available, it is worth to use them, because the accuracy increases. PLR (after optimization of parameters) stands out from other statistical models. The position of the deepest point of GSN (Fig. 2) probably plays a crucial role for the sexual dimorphism, as stated by the good performance of the visual assessment of this point and the fact that the A2 angle (posterior angle with the deepest point of the GSN as the apex) is included in all models.

Sex estimation of the subadult ilium prior to acetabular fusion.

Previous studies evaluating sexual dimorphism in subadult pelvic features present variable, and at times conflicting, conclusions. As a result, there is yet to be a consensus on whether the subadult pelvis can be used in sex estimation methods. This study aims to assess the forensic utility of ilium shape and greater sciatic notch morphology in sexing subadult pelves prior to acetabular fusion. A sample of 397 modern U.S. individuals with unfused acetabula (i.e., tri-radiate cartilages) aged birth to 14 years was queried from a larger sample of postmortem computed tomography scans. Elliptical Fourier analyses were performed on ilium and greater sciatic notch outlines and resultant PCs were evaluated for significant effects of sex and age. Greater sciatic notch metrics were also collected. Stepwise linear discriminant function analyses with leave-one-out cross-validation were performed on the PCs and metric variables. Analyses were performed on pooled samples, on age-specific cohort samples, and on samples that iteratively removed the youngest one-year cohort. Cross-validated correct classification rates ranged from 57% to 65% and no patterns were observed to support an appearance and/or consistent expression of sexually diagnostic traits. Based on the results, sex estimation using these features is not recommended in pelvic remains prior to acetabular fusion, although the sample sizes of individuals over 5 years of age were limited in this study. Future studies should focus on the sexually diagnostic ability of pelvic traits in subadult samples post-fusion of the acetabulum.

Differences in equine spinal kinematics between straight line and circle in trot.

Work on curved tracks, e.g. on circles, is commonplace within all forms of horse training. Horse movements in circles are naturally asymmetric, including the load distribution between inner and outer limbs. Within equestrian dressage the horse is expected to bend the back laterally to follow the circle, but this has never been studied scientifically. In the current study 12 horses were measured (optical motion capture, 100 Hz) trotting on left and right circles and on the straight without rider (soft surface). Data from markers placed along the spine indicated increased lateral bending to the inside (e.g. left bending on the left circle) of the thoracolumbar back (difference left circle vs. straight - 3.75°; right circle + 3.61°) and the neck (left - 5.23°; right + 4.80° vs. straight). Lateral bending ROM increased on the circle (+ 0.87° and + 0.62°). Individual variation in straight-circle differences was evident, but each horse was generally consistent over multiple trials. Differences in back movements between circle and straight were generally small and may or may not be visible, but accompanying changes in muscle activity and limb movements may add to the visual impression.

How low can we go? A skeletal maturity threshold for probabilistic visual sex estimation from immature human os coxae.

OBJECTIVES: The appearance of sexually dimorphic traits varies depending on the type of bone, age, environmental and genetic factors and is closely linked to skeletal maturation sequence. Subadult sex estimation currently shows inconsistent accuracy and methods do not incorporate indicators of maturation. The goal of this study is to apply the Santos et al. (2019) adult sex estimation method on virtually reconstructed subadult os coxae and account for pelvic maturation. MATERIAL AND METHODS: The right os coxae of 194 female and male individuals aged 11-30 years from Marseille, France were virtually reconstructed from computed tomography (CT) scans. Santos et al.'s (2019) 11 traits were scored as female, male, or indeterminate. Maturation of 10 pelvic epiphyseal sites was scored using a four-stage system (0-3) to obtain a composite maturity score from 1 to 30. RESULTS: Three maturity groups were identified based on composite maturity scores ranging from 0 to 30. Individuals with a composite maturity score of 15 or higher showed 98 % sex estimation accuracy and a 6 % indeterminate rate. Scores of 2 for the ischiatic tuberosity or 1 for the anterior superior iliac spine can be used as proxies for a composite maturity score of 15 and application on incomplete bones. DISCUSSION: Sexual dimorphism was observed in the epiphyseal maturation sequence and the development of sexually dimorphic pelvic traits. The Santos et al. (2019) method is applicable on immature individuals who meet a maturation threshold with comparable accuracy to adults, without relying on known or estimated age.

Deep Gluteal Syndrome: A Pain in the Buttock.

ABSTRACT: While buttock pain is a common complaint in sports medicine, deep gluteal syndrome (DGS) is a rare entity. DGS has been proposed as a unifying term referring to symptoms attributed to the various pain generators located in this region. While not all-inclusive, the diagnosis of DGS allows for focus on pathology of regionally associated muscles, tendons, and nerves in the clinical evaluation and management of posterior hip and buttock complaints. An understanding of the anatomic structures and their kinematic and topographic relationships in the deep gluteal space is pivotal in making accurate diagnoses and providing effective treatment. Because presenting clinical features may be unrevealing while imaging studies and diagnostic procedures lack supportive evidence, precise physical examination is essential in obtaining accurate diagnoses. Management of DGS involves focused rehabilitation with consideration of still clinically unproven adjunctive therapies, image-guided injections, and surgical intervention in refractory cases.

Computed tomography study of the relationship between pelvic incidence and bony contribution to lumbar lordosis in children.

There is little data regarding the relationship in children and how it may change with aging. The aim of this radiographic study was to define the relationship between pelvic incidence (PI) and segmental vertebral body lordosis through childhood. In 150 children, CT scans of the lumbar spine and pelvis were analyzed measuring PI, sacral table angle (STA), sacral kyphosis (SK), and segmental lordosis (SL) individually L1-L5. Children were grouped by age: (1) 0-60 months; (2) 61-120 months; (3) 121-185 months. Mean PI for the entire cohort was 40.4, mean SL for L1-0.6, L2 0.0, L3 1.8, L4, 4.7, and L5 11.4. There were 40 children in Group 1, 63 in Group 2 and 37 in Group 3. SL differed between age groups at all levels except at L2. L1 and L2 became more kyphotic with increasing age; L3, L4, and L5 became more lordotic with increasing age. The correlation between PI and SL at each level became stronger with increasing age. Similarly, the correlation between PI and STA and between PI and SK also became stronger with increasing age. As children mature, the relationship between PI and segmental lordosis at each level of the lumbar spine becomes stronger-the relationship between PI and lordosis trends toward that seen in the adult. Future work should aim to define when the adult PI-LL relationship is realized.

Development of a three-dimensional computer model of the canine pelvic limb including cruciate ligaments to simulate movement.

Gait analysis as subjective visual assessment forms the foundation of the veterinarian's lameness examination. Pelvic limb lameness is frequently seen in dogs and the stifle joint with its cruciate ligaments, is a main cause of lameness due to cruciate ligament deficiency. In this study, we developed an open-source three-dimensional musculoskeletal pelvic limb model of a 30 kg Labrador Retriever including cruciate ligaments, simulating the gait cycle of the walking movement with the open-source programs NMSBuilder (Institutio Ortopedico Rizzoli, Bologna, Italy) and OpenSim (National Center for Simulation in Rehabilitation Research (NCSRR), Stanford, CA, USA). The computer model generated muscle activations based on motion data. The computed activations were similar to experimental electromyogram data. Highest joint torque was in extension/flexion in the stifle joint at 54 Nm at 14% of the gait cycle with cruciate ligaments. Highest stifle joint reaction force was 408 N at 16% of the gait cycle and was reduced after adding cruciate ligaments. Especially the cranial cruciate ligament loads up to 102 N (34% body weight). Cranial cruciate ligament forces increase with stifle extension and decrease with stifle flexion. On the contrary, the caudal cruciate ligament loads up to 27 N (9% body weight) during the swing phase with a flexed stifle joint. The model was validated with electromyogram data. The model's predictions are plausible because joint torques and forces match the applied ground reaction forces in curve progression and in timing. This model forms a basis for further investigations into stifle surgery after cruciate ligament deficiency.

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.