Outline Shape Analysis on the Trochlear Constriction and Olecranon Fossa of the Humerus: Insights for Sex Estimation and a New Computational Tool.

Sex estimation through visual analysis of the distal humerus can contribute to establishing the biological profile of an unidentified skeletal individual. Using statistical shape modeling, the trochlear constriction open curves and olecranon fossa closed outlines of 151 humeri were digitized and analyzed. The shape configurations exhibited strikingly different degrees of sexual dimorphism when evaluated using linear discriminant analysis with leave-one-out cross-validation. The trochlear constriction performed poorly, correctly classifying 63.6% of the individuals. However, the olecranon fossa showed high sexual dimorphism, presenting a 94.0% accuracy. A simpler model using only two principal components was also generated. While the accuracy is slightly inferior (88.1%), it has the advantage of being constrained to bidimensional components that were translated into morphoscopic variables within a simulator interface. This allowed us to implement the method through a web application that does not require users to be trained in landmark digitization or have knowledge of geometric morphometrics.

A glimpse from the past: osteoporosis and osteoporotic fractures in a Portuguese identified skeletal sample.

UNLABELLED: The diachronic variation of etiological factors, like longevity or diet, affected the prevalence of osteoporosis and the so-called osteoporotic fractures in the past. As such, it is important to understand the epidemiology of this disease in historical populations; with behaviors and customs that were unalike the modern westernized lifestyle. OBJECTIVES: The main objective of this study is to characterize the epidemiological patterns of osteoporosis and related fractures in an identified Portuguese skeletal sample from the mid 19th - early 20th centuries. MATERIALS AND METHODS: The sample studied comprised 196 skeletal individuals with known sex and age-at-death, housed at the University of Coimbra. Bone mineral density (BMD) was evaluated in the proximal femur through dual X-ray absorptiometry and osteoporotic fractures were recorded according to clinical and paleopathological protocols. RESULTS: BMD decreased significantly with age-at-death, both at the ROI «Total hip¼ and the ROI «Neck¼. At the «Total hip¼, peak bone mass (PBM) was achieved early (20-29 years age group) in both sexes. In the study-group as a whole, BMD was significantly higher in males when compared to females. As expected, the prevalence of osteoporosis in the proximal femur is higher in women and rises steeply with age. Comparisons with two modern Portuguese samples showed an equivalent pattern of BMD reduction. Nonetheless, BMD is usually lower in the skeletal sample. Women with osteoporosis had a much larger probability of showing a fragility fracture than women diagnosed with «normal¼ BMD or osteopenia. CONCLUSIONS: In spite of enormous lifestyle differences, the epidemiological pattern of bone mass decrease in a Portuguese skeletal sample is strikingly similar to the ones observed in modern populations. This study adds further data to the recent notion that osteoporosis is a disease with deep roots in the past.