 The overall goal of this technology development initiative is to greatly advance the clinical diagnosis and treatment of musculoskeletal impairments as they relate to joint function. The primary focus of this protocol is to initially develop and ultimately validate a combined set of tools virtual functional anatomy - VFA that will enable the accurate and precise measurement, analysis and visualization of three-dimensional 3D static and dynamic musculoskeletal anatomy i.e., bone shape, skeletal kinematics, tendon and ligament strain, muscle force, and joint space from imaging data. We plan to merge and extend our existing MR imaging and analysis capabilities with ultrasound imaging and analysis for the development and implementation of a highly accurate, imaging-based measurement and analysis technique for the non-invasive quantification of complete joint anatomy and tissue dynamics during functional movements. In short, we plan to develop a method for creating 3D digital images of loaded and moving joint tissues bone, cartilage, and connective tissues that reveal joint contact patterns and tissue loads. In conjunction with building this tool, we will evaluate the variability of bone shape across subjects, the sensitivity of defined joint posture translation and rotation of one bone relative to another to osteo-based coordinate system definition, and the ability to ultimately use these tools to document and evaluate the function of normal and impaired joint structures e.g., ACL rupture, patella tracking syndrome under simulated conditions experienced during activities of daily living. 