(in french)There are two actual challenges in the simulation of the human body for medical purpose: the ability to modelcomplex structures and their interactions, and the ability to accurately represent reality. In this article we show furtherdevelopments of a model presented some years ago to address the former and we present some solutions concerningthe latter. In this model, based on an object-oriented modeling framework, soft tissues are considered as three-dimensional elastic bodies and bones are considered as three-dimensional rigid bodies. All these objects evolves in aviscous medium and are submitted both to internal cohesive forces and to external attractive or interactional forceswith other objects (links). An explicit algorithm is developed to compute the dynamic evolution of these objects whileguarantying the necessary constraints. The elastic/rigid connections and tissues incompressibility are considered asconstraints. The model is first presented, then we explain the methodology to apply to give a qualitative as well as aquantitative validation.