Originally Posted by Jaeger

That may be true, but even manufacturers of full face motorcycle helmets make pretty modest claims about how much protection they offer in a 40 mph impact. It's possible the little bit of foam and plastic in a bike helmet saved his life, and it's possible it had no effect at all. If these helmets had a fraction of the magical protective capabilities that advocates claim they have he should have been able to get up, see to his other injuries and then pose cheerfully for a picture with his cracked helmet. Instead an impact to the head with the helmet on still produced a very serious head injury.