The goal of this study is to develop new biomechanical models representing the non-linear behavior of costo-vertebral and costo-transverse joints (CVCT). Three models of the CVCT joints were developed using different types of beams : 3D elastic beams; linear 3D plastic beams ; and multi-linear 3D plastic beams. Moments from -0.6 to 0.6 Nm by increment of 0.1 Nm were applied on the rib of each model and compared to experiments data from 11 cadaveric spines for levels T1-T2, T5-T6 and T9-T10. In each case, the mechanical and geometrical properties were iteratively changed to best represent CVCT joints experimental behavior. This study produced three different models that can be used to represent the local behavior of the CVCT joints. These models will be extended to the intermediate anatomical levels by interpolation and included in our global model of the trunk.