The objective of this project is to investigate the relationship between the morphologic and architectural configuration of trabecular bone and its mechanical properties. During the first phase of investigation, we have developed the capabilities of quantifying three-dimensional morphology, connectivity, and anisotropy of trabecular bone samples utilizing a unique microcomputed tomography scanner. In addition, we have experimentally derived an empirical relationship between orthogonal moduli and trabecular morphology. The specific aims of this proposal are: 1. To validate and evaluate the use of a new three-dimensional morphologic and structural algorithm which we have designated the "configuration method". 2. To experimentally develop a more generalized structure function relationship for human trabecular bone in order to predict the Young's and shear moduli from morphologic and architectural measures. 3. To experimentally determine the variation in trabecular tissue moduli as a function of age and anatomic location. 4. Utilize a microstructural approach to analytically and experimentally investigate the optimality of trabecular structure and perform a sensitivity analysis on the morphologic and architectural factors that contribute to mechanical integrity. The project will involve measuring the trabecular bone morphology and architecture utilizing microcomputed tomography scanning, continuum level materials testing, and microstructural materials testing. The analtyical procedures will include finite element based optimization algorithms along with of homogenization theory. The results of these studies will provide evidence for trabecular bone remodeling strategies related to structural optimization. This information will support continuing efforts towards understanding relationships between physiologic, mechanical, or environmental alterations and trabecular bone.