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Abstract ObjectiveThis project investigates trabecular bone structural variation in the proximal humerus and femur of hunter‐gatherer, mixed‐strategy agricultural, medieval, and human groups to address three questions: (a) What is the extent of trabecular bone structural variation in the humerus and femur between populations with different inferred activity levels? (b) How does variation in the proximal humerus relate to variation in the proximal femur? (c) Are trabecular bone microstructural variables sexually dimorphic? MethodsThe proximal humerus and femur of 73 adults from five human groups with distinct subsistence strategies were scanned using a micro‐computed tomography system. Centralized volumes of interest within the humeral and femoral heads were extracted and analyzed to quantify bone volume fraction, trabecular thickness, trabecular separation, connectivity density, degree of anisotropy, and bone surface density. ResultsIn the humerus and femur, groups with the highest inferred activity levels have higher bone volume fraction and trabecular thickness, and lower bone surface density than those with lower inferred activity levels. However, the humeral pattern does not exactly mirror that of the femur, which demonstrates a steeper gradient of difference between subsistence groups. No significant differences were identified in trabecular separation. No consistent patterns of sexual dimorphism were present in the humerus or femur. ConclusionsReduced skeletal robusticity of proximal humeral and femoral trabecular bone corresponds with reduced activity level inferred from subsistence strategy. However, human trabecular bone structural variation is complex and future work should explore how other factors (diet, climate, genetics, disease load, etc.), in addition to activity, influence bone structural variation.
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Using point clouds to investigate the relationship between trabecular bone phenotype and behavior: An example utilizing the human calcaneus
Abstract ObjectivesThe objective of this study is to demonstrate a new method for analyzing trabecular bone volume fraction and degree of anisotropy in three dimensions. MethodsWe use a combination of automatic mesh registration, point‐cloud correspondence registration, andP‐value corrected univariate statistical tests to compare bone volume fraction and degree of anisotropy on a point by point basis across the entire calcaneus of two human groups with different subsistence strategies. ResultsWe found that the patterns of high and low bone volume fraction and degree of anisotropy distribution between the Black Earth (hunter‐gatherers) and Norris Farms (mixed‐strategy agriculturalists) are very similar, but differ in magnitude. The hunter‐gatherers exhibit higher levels of bone volume fraction and less anisotropic trabecular bone organization. Additionally, patterns of bone volume fraction and degree of anisotropy in the calcaneus correspond well with biomechanical expectations of relative forces experienced during walking and running. ConclusionsWe conclude that comparing site‐specific, localized differences in trabecular bone variables such as bone volume fraction and degree of anisotropy in three‐dimensions is a powerful analytical tool. This method makes it possible to determine where similarities and differences between groups are located within the whole skeletal element of interest. The visualization of multiple variables also provides a way for researchers to see how the trabecular bone variables interact within the morphology, and allows for a more nuanced understanding of how they relate to one another and the broader mechanical environment.
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- Award ID(s):
- 1719187
- PAR ID:
- 10450829
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- American Journal of Human Biology
- Volume:
- 33
- Issue:
- 2
- ISSN:
- 1042-0533
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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