A linear elastic modulus was defined for each of the following materials: vein wall (0.133MPa), artery wall (2MPa) [7], muscle and fat were assumed to have the same properties (elastic modulus 0.012MPa) [2]. All materials were assumed to be nearly incompressible with a Poisson’s ratio of 0.49. The degrees of freedom of nodes at the bone/tissue boundary were fixed, thus constraining the bone location.