Accident cases are examined to determine the injury mechanism for foot/ankle moderate and greater injuries in vehicle crashes. The authors examine 480 in-depth cases from the National Accident Sampling System for the years 1979 through 1987. An injury mechanism -- a description of how the foot/ankle physically interacted with the interior of the vehicle -- is assigned to each of the injured occupants. For the accidents in which the 480 occupants were injures, the more prominent types of vehicle collisions are characterized.