This paper proposes a model of the skin stiffness including the effect of the pressure of the radial artery, which is transmitted to the palpating doctor's hand. The transmitted stiffness is modeled with serially linked skin and radial artery stiffness. The stiffness of the radial artery comes from the inner pressure and stiffness of the artery wall. The relation between the stiffness and the inner pressure of the radial artery is experimentally determined. The proposed model is used to control the haptic interface of a training simulation of the radial artery palpation.