A few weeks I posted about 5 common myths about pain. Over the next few posts I will try to explain why each is a myth. Here is that list again if you didn’t see it or don’t remember it.
- Pain comes from a specific structure in your body, for example a joint, bone, or muscle.
- The amount of pain some is experiencing is directly related to the amount of structural damage or seriousness of an injury.
- Pain signals are sent from the body to the brain
- Pain is a completely physical experience, separate from thoughts or emotions
- Pain is in your head or psychosomatic if no physical injury or signs are present, for example negative scans or no obvious injury
We tackled the 1st myth (actually #3 on the list) in this post https://ascentpt.wordpress.com/2015/03/11/pain-myth-1/
Today I will talk about #1 on our list. Pain does not need to come from one specific area. And if it does, that specific structure is our brain. Many people when they present for therapy want to know exactly what physical structure is the problem. Is it a herniated disk? My worn out knee joint? Which tendon? As I wrote about last time if a structure is injured, damaged or inflammed the body will send nociceptive signals on to the brain. If the brain perceives this as a threat it can respond by giving you a pain experience. You may, for example, injure an ankle ligament when you step in a hole. When the ligament has enough stress placed on it, it will send nociceptive signals onto the brain. The brain then decides whether pain is an appropriate response and for how long. So, a specific tissue is sending signals and pain may be a response. But this is not always the case.
In some situations people have what is known as phantom pain. People have lost a limb to an accident or other amputation, but they can continue to feel pain in the limb despite it not being there anymore. If there are no sensors to send signals to the brain, or nerves to send signals back to the limb how can there be pain?
Our brain has an area in it called the homunculus And in this area we have neurons that are devoted to specific parts of our body. This can be thought of as a “virtual body”.
When people have persistent pain, brain imaging has shown that this part of the brain can change. The areas of the brain can become less clearly defined and may leak into one another. This is called “smudging”. When an area has an initial injury but stays painful for a long time, pain may spread or even seem to jump around. To many people this seems like the structures must be becoming more injured, or new structures are being affected. But, in many cases this may mean there is a change in how we are processing the information. No new specific structures are injured or damaged, the nervous system is responding differently as it changes. The longer pain persists the more changes happen.
So, as you can see pain is more complex than a tissue becoming damaged and pain responding. Many things happen through our nervous system that can make things complicated. But, you can experience pain from a response to a specific tissue, or get a generalized response that may seem to affect many different areas, or in some cases experience pain in a part of the body that no longer is present.