It's all in your head

Last week I attended a course called Explain Pain.

Most of the people that walk through my door are in pain. Sometimes it's simple enough to work out why, what's injured and what needs to be done to make it better. I've always felt that one of the most important parts of treatment is the education side of it. Making sure the client understands why they are injured, why they have pain and what they can do to prevent it happening again. Sometimes people say to me "I wonder if this pain is all in my head" and that phrase definitely has a negative connotation to it. The person feels they are making too much of it or even making it all up. In actual fact the opposite is true.

One of the things that I find slightly mind blowing is that we don't feel pain in our tissues. We don't have "Pain" Receptors. Instead we have sensory nerve endings that sense heat, cold, pressure and stretch. All of these sensations can move from ok to dangerous. For example, have you ever put your fingers under a hot running tap as it warms up. The sensation goes from cool, to pleasantly warm and at some point will get uncomfortably hot and you'll take your hand out from under the tap before it burns. This is because your heat receptors are sending increasingly quick impulses to your brain, and in your brain these signals will be interpreted as dangerous when they reach a certain level. At that point the brain will inform us that we are in pain, the pain of excess heat, the brain can also tell us "It's too hot, it's dangerous and it's your middle finger". The same with stretch, take your middle finger and pull it back slowly, you'll feel a stretch sensation. The stretch nerve endings are sending signals to your brain, the brain tells us "Middle finger is being stretched back", keep pulling it and you feel start to feel pain, you will perceive it in your middle finger, this is your brain telling you "this stretch is going too far, it's dangerous, it's your middle finger...STOP!".

When tissue isn't rescued from these sensations before an injury occurs, damage happens. Skin is burnt; and ligaments, muscles and cartilage are torn. At this point, our bodies do this most amazing thing - they heal us. A hugely complex process starts whereby blood vessels that have been torn are patched up, excess fluid (swelling) is leaked into our tissues to splint the area, white blood cells head into the area to clear up debris, and a variety of chemicals are released that push this healing process along. New tissue is laid down and eventually the new tissue is remodelled and the ligament or muscle is mended. It is a marvellous process, so why is it painful?

First of all, that excess fluid puts pressure onto pressure receptors in the damaged area, and they send increasingly frantic signals to our brain which say "too much pressure", and so our brain tells us "there's pain on the outside of your ankle".

Secondly, the chemicals that are released irritate the sensory nerve endings, which causes them to send danger signals to the brain too, which are interpreted as pain - the level of which is dependent on the amount of irritation at the injury site.

As the tissues return to normal (over days and sometimes weeks), the chemicals are taken from the area and the extra tissue fluid is absorbed and removed by our circulatory system. The sensory nerve endings are no longer irritated, the brain no longer perceives pain.

So, yes, it is all in your head. That's just how pain works.

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