L’analyse biomécanique peut être utilisée pour comprendre et interpréter l’impact de la mobilité et du climat sur la morphologie squelettique des populations humaines préhistoriques en mesurant les propriétés mécaniques des os longs. Le comportement et le climat font parties de plusieurs facteurs non-génétiques qui peuvent avoir un impact sur l’adaptation fonctionnelle osseuse en influençant les charges mécaniques sur le squelette et déclenchant le processus de modelage osseux. Cette étude se concentre sur les changements au niveau macrostructural des os longs : les propriétés mécaniques sont ainsi calculées sur plusieurs sections en coupe afin de mesurer la robustesse et la géométrie diaphysaire. Mon projet consiste à développer une collection de référence incluant quatre populations holocènes du Nord du Canada dont les Inuit Sadlermiut et trois échantillons d’Euro-Canadiens venant de Notre-Dame, Pointe-aux-Trembles et Sainte-Marie. L’objectif est de contrôler pour différents facteurs environnementaux afin de mieux comprendre l’effet de la mobilité et le climat sur la morphologie squelettique humaine. Les propriétés mécaniques d’os longs incluant l’humérus, le fémur et le tibia sont mesurées par tomodensitométrie quantitative périphérique (pQCT). Ces données sont ensuite incluses dans une méta-analyse dont les données sont tirées de la littérature scientifique, comparant d’autres populations archéologiques qui avaient différents modes de subsistance et habitaient diverses zones climatiques. Les données démontrent que les Inuit Sadlermiut ont des membres supérieurs et inférieurs plus robustes que trois échantillons de populations d’Euro-Canadiens qui ne diffèrent pas l’un de l’autre. La robustesse squelettique chez les Sadlermiut proviendrait de leur haut niveau d’activité physique nécessité par leur mode de vie de chasseur-cueilleur dans un climat rude et froid. De plus, la méta-analyse portant sur la mobilité a déterminé que le type et l’intensité des charges mécaniques habituelles ont une influence importante sur la morphologie des membres supérieurs et inférieurs tandis que celle portant sur le climat démontre qu’une relation est significative avec l’humérus. Ainsi, ce projet atteste que le processus de modelage osseux est multifactoriel et que le degré d’influence des facteurs comportementaux et environnementaux n’est pas uniforme sur le squelette. / Biomechanical analyses have been used to study the impact of mobility and climate on the skeletal morphology of past human populations through the measure of the cross-sectional geometry of long bones. Behavior and climate are one of the many non-genetic factors that can impact bone functional adaptation by influencing mechanical loads on the skeleton and triggering the bone modeling process. The present study focuses on the structural changes occurring at the macrolevel of long bones, more specifically robusticity and shape, by calculating mechanical properties at several cross-sectional locations. This project consists of creating a reference collection using four Holocene populations from northern Canada including Sadlermiut Inuit and three Euro-Canadian samples from Notre-Dame, Pointe-aux-Trembles and Sainte-Marie. The objective is to control for different environmental factors to better understand the impact of mobility and climate on human postcranial morphology. Cross-sectional properties were measured in the humerus, femur and tibia using a portable peripheral quantitative computed tomography (pQCT). These data were then input into a meta-analysis that included data, drawn from the scientific literature, from other archaeological populations with different modes of subsistence and inhabiting various climate types. The results showed that Sadlermiut Inuit had more robust upper and lower limbs than all three samples of Euro-Canadians who did not differ significantly from one another. The high measures of robusticity among Sadlermiut were attributed to the strenuous physical activity demanded by their hunting and gathering mode of subsistence in cold and harsh environmental conditions. Furthermore, the meta-analysis on mobility demonstrated that the type and intensity of habitual mechanical loading on the skeleton has a significant influence on the upper and lower limbs whereas the meta-analysis pertaining to climate only had a significant relationship with the humerus. Essentially, this project highlights the multifactorial nature of the bone modeling process and that the level of influence of behavioral versus climatic factors is not uniform throughout the skeleton.

This project investigas humeral torsion and activity-related change in the human upper limb. Increased humeral torsion angles have been identified in the professional throwing athlete and may be associated with strenuous activity. The nature of humeral torsion as an osteogenic response to the strain environment is investigated to identify its role in the behavioural morphology of the upper limb. These physical manifestations of strenuous physical activity provide an insight into the make-up of medieval armies prior to the establishment of standing armies. Populations analysed include two blade-injured samples, Towton and a subsample of blade-injured men from the Priory of St. Andrew, Fishergate, York. The men from the Mary Rose, a Tudor warship are also investigated. Other samples analysed include the rural sites of Wharram Percy and Hickleton, the urban cemeteries from the Priory of St. Andrew, Fishergate,York and the leprosarium of Sts. James and Mary Magdalene, Chichester, the modern cadaver-based Terry collection and non-human primates, Gorilla sp., Pan sp., Pongo sp., and Macaca sp.. Measurement of the humeral torsion angle and external measurements and indices of architecture, articulations and robusticity are employed. Cross-sectional geometric properties are investigated using CT imaging of the paired humeri from a sub-sample of blade-injured individuals and a comparative sample of those who were not. Bilateral asymmetry is investigated to identify the role of plasticity within the humerus and to reveal aspects of limb dominance. The results are compared with non-human primate species to obtain insight into inter-species differences. Results indicate the humeral torsion is not ontogenetically constrained, but is highly variable between and within populations, individuals and even between sides. Biomechanical analyses indicate that in the Towton population, humeral torsion may serve as part of a two-stage adaptation, in which the architecture is modified to enable greater biomechanical efficiency in distributing strain, reducing the need of increased cortical thickness. Changes in humeral torsion related to strenuous activity have been identified, although in the blade-injured samples it is decreased torsion angles, w hile in the comparative sample it is increased torsion angles that significantly correlate with limb hypertrophy. Humeral torsion appears to be influenced by other measurementd of humeral architecture, specifically, the amount of anterior bowing and anterior curvature to the distal humeral shaft. This work demonstrates the need for individual rather than population-based analyses, as the heterogeneity within population samples obscures individual variation in activity patterns. This analysis provides baseline data for typical populations of the Middle Ages. From this, it is then possible to investigate the individual within this baseline, to identify those who stand out from their samples through habitual, strenuous activity patterns. Movement patterns identified related to warfare include those consistent with the use of the longbow in the Towton sample and the use of a sword in the Fishergate blade-injured sample. These men, and those of the Mary Rose, appear to have either been selected for combat based on size, or benefited from a more nutritious diet during growth. / Arts and Humanities Research Board (AHRB), Francis Raymond Hudson Fund, Andy Jagger Fund.