Coup and contrecoup injuries can occur individually or together. Diffuse axonal injury is the most prevalent pathology of coup contrecoup. The exact mechanism for the injuries, especially contrecoup injuries, is a subject of much debate. Contrecoup injury may be produced by tensile forces. In the 17th century, Jean Louis Petit described contrecoup injuries. In the crash he suffered a contrecoup injury to the frontal lobes of his brain.