Part of the show Brainwashing and the Science of Pain
Raphael in California asked:
Why is it that when you pinch the excess skin on your elbow you don't feel the pain even if you pinch really quite hard?
Pinching is a classic example of mechanical pain. If you squeeze mechanically with pressure on any part of your body it's actually quite hard to make it painful unless you've got a bruise or some damage there already. What you might like to do is to take a pin and very carefully try the pin on that part of the elbow compared to another part of the body. What you'll probably see is that the perception of pain to that pin prick is actually pretty similar. It's just specific to this mechanical crushing type of pain and feels as though there are no pain receptors in that part of the skin. That's actually not the case.