The pelvic floor gives support to the organs in the abdominal cavity. Using the dataset made public in [11] we have reconstructed the geometry of one of the most important parts of the pelvic floor, the levator ani, using NURB surfaces. Once the surface is triangulated, this mesh is used in a finite element analysis with shell elements.Based on the 3D behavior of the muscle we have constructed a shell that takes into account the direction of the muscle fibers and the incompressibility of the tissue. The constitutive model for the isotropic strain energy and the passive strain energy stored in the fibers are adapted from Humphrey's model for cardiac muscles. To this the active behavior of the skeletal muscle is added.We present preliminary results of a simulation of the levator ani muscle under pressure and with active contraction. This research aims at helping predict the damages to the pelvic floor that can occur during childbirth.

This paper proposes a mass-spring model of the dynamics of a human thigh based on real data acquired. Using a force sensor mounted on a robot arm the deformation of the thigh with respect to an external force is measured. The stress-strain curves we obtained exhibit a strong non-linearity due to the incompressibility of the human tissue. Hence, we propose a two-layer model of the thigh using both linear and non-linear visco-elastic springs to simulate the observed behaviour. The parameters of the springs are estimated using a least-squares minimisation method. Finally, we discuss the feasibility of our model as part of a fully functional simulator coupled with a haptic interface to train practitioners for echographic exams.

This paper proposes a method for interfacing a force-feedback device of type PHANToM to a springdamper model of the human thigh. The model was de ned f r om experimental data and it is simulated u sing implicit integration. The main di culty in this is that while the PHANToM needs to receive the force values at a rate of 1KHz, the physical model runs at a maximum speed of 100Hz. Supplying forces at this frequency leads to unrealistic vibration in the force f e edback. The novelty of our approach is the use of a local model supplying reliable force values at a high frequency. The purpose of this work is to contribute for the implementation of an echographic simulator with force-feedback.

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