Guess where the pain in your back comes from? Your head.
Before you slap me with your disability parking badge, hear me out; I’m NOT saying that “it’s all in your head”. Back pain affects nearly a billion people a day around the world, and I definitely don’t want to offend that many people. But what is it that makes it so difficult to pin down the cause of each back pain episode? I’m going to argue that it’s your head – or more precisely, your brain.
Fact 1. There is no such thing as a “pain nerve” or “pain sensitive nerve” in your body. Your body has lots of nerves, and the fibres within those nerves are sensitive to different things. Broadly speaking these are mechanical pressure, temperature, and “noxious” substances – like the chemicals your body produces during inflammation and when it’s been injured. These “nociceptor” nerve fibres send impulses up to your spinal cord to inform it that something has gone wrong.
Fact 2. Nociceptors can “fire” without you feeling pain.
Fact 3. The amount of pain you feel is not related to the number of nociceptors firing.
Fact 4. Brain activity (and your physical and social environment) influences which incoming messages get through to your consciousness.
Fact 5. As shown in the image, you have a map of your physical body in your brain (collections of nerves relate to specific body parts). This is why amputees can still experience pain in the missing limb. The brain projects pain into that body part even though that body part isn’t there anymore.
Feeling pain in your body is a bit like hearing a sound. There are nerve endings inside your ear which “fire” when sound waves hit your eardrum. These nerve impulses are interpreted by the brain as sound. It’s the same with sight; special nerve endings at the back of the eye (in your retina) fire when light hits the eye. These messages are then interpreted by the brain to create an image of the world around you – which you “see”. Pain is just like this: the messages coming into the brain are interpreted by the brain, and then pain may be projected back into that part of the body.
So, if your back doesn’t hurt on Monday or Wednesday, but does hurt on Tuesday, is it because you twisted it awkwardly on Tuesday but it got better over night? Or is it because your brain was in a greater state of alarm so it projected pain into your lower back on Tuesday, but life was good on Monday and Wednesday, so your back didn’t hurt?
- Pain is very real. Everyone has their own pain experience.
- The brain is hugely influential in your pain experience – no brain, no pain!!
Next time you’re in for an appointment, we can talk more about this, or feel free to email me. If you’ve a seemingly strange pain experience, I’d love to hear about it.