Rusty Nails
We remember
- Location
 - Living in the slow lane
 
We do all need to remember that accidents - and impacts - come in many flavours. Nevertheless, I shall comment on this specific issue:
Actually, I think we're all quite good at this. Imagine we're standing on a safe surface (trampoline, wodevva ..) I challenge you to hold your hands by hour sides as I gently topple you over sideways.
When you land on your hip/shoulder/etc, I'd wager that most times your average neck muscles will keep your head from impact. On the occasions it *does* hit something, it will be a lot more gently than your shoulder hits.
No superhuman powers required!
I have had many falls on my bikes when I avoided my head hitting the floor.
I have had two falls when I didn't, travelling at a greater speed.
Once my head hit metal railings at the side of the road. No damage to me, except scratches on the helmet.
Once I fell, hit my head on the road taking a chunk out of my helmet and waking up as the paramedic put me into the ambulance on the way to hospital where I was diagnosed with concussion and bleeding on the brain. No damage to the surface of my head, just the helmet.
I doubt in either of the last two I would have somehow avoided hitting my bare head.
				
  Two torn ligaments and one concussion since I started cycling again 11 years ago after a break of almost 40 years!  I've virtually given up off road mtb riding these days and I think that at 74 I'll stick to the road, although not literally I hope.