This paper presents a physically-based biomechanical model for muscle
deformation by FEM (Finite Element Modeling) and volume graphics.
Hierarchy voxel meshes are reconstructed by scan-based muscle images
for FEM simulation and rendering.  Physiological muscle force is
considered and linear elastic muscle models for both static and
dynamic cases are simulated by FEM.  3D wireframe, polygon surface
and volume rendering techniques are applied to show low-resolution
real-time muscle deformation processes as well as realistic animation.
Resulting simulations and renderings demonstrate very promising performance
of the new model. An algorithm is proposed to employ our approach in medical
applications, such as surgical simulation, cutting, treatment planning, 
physician training and outcome prediction, based on scanned images.