This study lies within the scope of passive road safety, and more particularly injury mechanisms of the abdominal area. The finite element modeling, which makes it possible to simulate a road accident and to observe the possible bone fractures or internal tissue injuries, allows large projections in the comprehension of injury mechanisms. However, the digital models already available and used in accidentology do not offer as one very simplified description of the diaphragm, as well for its geometry as for its bracing aspect and the modifications that this could induce in the behavior of abdominal organs and vessels at impact. In order to develop an accurate model of diaphragm for road safety research, a 3D reconstruction was performed, based on a sitting post-mortem Human subject sections. The resulting geometry was then turned into a segmented mechanical component (using the finite element method) and included in a full human model already available. The result is a valuable tool to improve the knowledge of injury mechanisms involved in car crashes at the abdominal level.