Spinal cord injuries are most commonly caused by motor vehicle accidents. The next most frequent causes are falls and acts of violence. Sports-related spinal cord injuries occur more commonly in children and teenagers, while work-related injuries (especially from construction work) predominate in adults. A complete spinal cord injury produces total loss of all motor and sensory function below the level of injury. Almost one half of all spinal cord injuries are complete. Even in complete spinal cord injuries, the spinal cord is rarely cut or transected. More commonly, loss of function is caused by a contusion or bruise in the spinal cord or by compromise of blood flow to the injured part of the spinal cord.