Knowledge of stress distributions in the arterial wall is important for many reasons. In the study of the propagation of pulse waves, one must know the incremental modulus of the elasticity that changes with the stress level. In the study of circulation control, the action of the vascular smooth muscle, which depends on its local stress level (see review in Fung, 1984), must be evaluated. In the study of atherogenesis, one must know the stress distribution in the vessel wall because the tensile and shear stress can alter the local wall permea-bility and pressure gradient which is the force that drives the fluid in or out of the vessel wall (Chuong and Fung, 1983). Accurate evaluation of stress distributions in the arterial wall is therefore an important step toward a better understanding of various physiological functions and pathological mechanisms associated with the circulatory system.