NTRODUCTION Mechanically, the healthy human skeleton is an optimal structure which has adapted itsform in response to its function. In order to perform any biomechanical analysis of themusculoskeletal system, it is necessary to understand the underlying anatomy since thiscomprises the geometry, material properties, and some of the boundary conditions of theproblem. Our approach will be to learn enough anatomy to enable us to perform ouranalyses. Depending on the goal of the particular analysis, a more detailed treatment ofthe anatomy may be necessary. For example, in some cases, it may be sufficient to modelthe femoral diaphysis as a hollow circular cylinder, in other cases it may be necessary toaccount for its non-circular, asymmetric cross-section. This decision is up to the analystand that decision making process is a major challenge to the bioengineer.