Injury mechanisms in renal trauma were investigated by analyzing the stress distributions within a two-dimensional computer-simulated model of the kidney. In biomechanics, damage to biological tissue is primarily caused by stresses resulting in tissue deformation beyond recovery limits. Segmental surface force was applied to the model and the resulting stress distributions were analyzed. Maximum stress concentrations were found at the periphery of the kidney model. Stresses were caused by the combined effect of the applied force and the reaction generated by the liquid-filled inner compartment as a function of its hydrostatic pressure. Maximum stress concentrations corresponded to typical injury sites observed clinically. Our findings suggest that a similar mechanism may play a crucial role in renal trauma. Renal injuries as well as the higher trauma susceptibility of hydronephrotic kidneys and renal cysts could thus be explained. The role of computer models in injury biomechanics research is discussed.