Quantitative and spatial analysis of the microscopic bone structures of deer (Odocoileus virginianus), dog (Canis familiaris), and pig (Sus scrofa domesticus)

Abstract

Structure and morphology of bone tissue are variable by species. The influence of different factors on structure and morphology is still debated. Qualifying and quantifying these differences are necessary in the evaluation of fragmentary bones in order to identify specific species. To understand the influence of species of origin on the microscopic structure of bone tissue, the influence of developmental and biomechanical forces specific to a skeletal element must also be assessed. This research is a preliminary analysis of the histological bone structures in terms of their area, density and spatial organization. To achieve this research goal, the cross-section of three major skeletal structures of three common quadrupeds ubiquitous across North America and commonly found in association with human remains were compared. The study analyzed the mid-shaft cross-section of six femora, five humeri, and six mid-thoracic ribs of the white-tailed deer (Odocoileus virginianus); six femora, six humeri, and six mid-thoracic ribs of the domestic dog (Canis familiaris); and five femora, four humeri, and six mid-thoracic ribs of the domestic pig (Sus scrofa domesticus). The cross-section of each skeletal element was divided into eight sections along anatomically recognized body planes. All histomorphometric measurements and observations were taken within these sections to explore the spatial organization of the microscopic structures across the mid-shaft cross-section. Plexiform bone observations suggest not only species-specific presence and absence of this bone structure but a relation to the skeletal element. There was an almost complete absence of plexiform bone in the mid-thoracic rib and reduced presence in the humerus of all three species. Secondary osteon area isolated pig from the other two species, in all three skeletal elements, suggesting a species-specific difference in osteon development. On the other hand, though similar in area, deer and dog showed interspecies, parallel patterns between like elements (humerus and humerus, femur and femur). Secondary osteon density followed an expected trend of increasing density associated with older animals. The implications for this study are two-fold. First, the results suggest future avenues of research for histologically differentiating species in both forensic and archaeological contexts. Second, the results support the hypothesis that it is important to incorporate a spatial analysis of microscopic structure distribution as an additional source of information about species and bone element differences in microscopic arrangements of the bone tissue.