On lap 7, the second lap at racing speed, Senna’s car left the racing line at the 190 mph Tamburello corner, ran in a straight line off the track and struck an unprotected concrete barrier.
Telemetry shows he left the track at 310 km/h (190 mph) and was able to slow the car down by braking to 218 km/h (135 mph) in slightly under 2 seconds before hitting the wall. The car hit the wall at a shallow angle, tearing off the right front wheel and nose cone and spun to a halt. After Senna’s car stopped he was initially motionless in the cockpit. After about ten seconds, as recorded by the close-up aerial footage, his head was seen to move about one inch to the left before returning to where it was. Thereafter he did not move again. What appeared to have happened was that the right front wheel shot up upon impact and entered the cockpit, striking the right frontal area of his helmet. The violence of the wheel’s impact pushed his head back against the headrest, causing fatal skull fractures. A piece of suspension attached to the wheel had partially penetrated his Bell M3 helmet and caused trauma to his head.In addition, it appeared that a jagged piece of the upright assembly had penetrated the helmet visor just above his right eye. Senna was using a medium sized (58 cm) M3 helmet with a new “thin” Bell visor. Any one of the three injuries would probably have killed him.
After the crash it was immediately evident that Senna had suffered some form of injury, because his helmet was seen to be motionless and leaning slightly to the right. The subtle movement of his head in the seconds that followed raised false hopes. Moments after the crash, Angelo Orsi, a photographer and a friend of Senna, took photographs of Senna in the car after his helmet was removed and Senna being treated before marshals blocked his view. Despite receiving numerous offers, the photographs have only been seen by Orsi and the Senna family who insisted that Orsi not publish the photographs