  A 3D biomechanical finite element model of the face is presented. Muscles are
represented by piece-wise uniaxial tension cable elements linking the insertion
points. Such insertion points are specific entities differing from nodes of the
finite element mesh, which makes possible to change either the mesh or the
muscle implementation totally independently of each other. Lip/teeth and upper
lip/lower lip contacts are also modeled. Simulations of smiling and of an
Orbicularis Oris activation are presented and interpreted. The importance of a
proper account of contacts and of an accurate anatomical description is shown
