When you experience pain in a specific location in your body, you assume that something is wrong in the area where you feel the pain. In most cases, you would be correct.
However, your chiropractor knows there are occasions when you feel pain in one area of your body and the problem is really in another area – sometimes far from the spot where you feel the symptoms. This is known as referred pain.
What Causes Referred Pain?
Simply put, referred pain is the brain’s misinterpretation of information.
Information about everything in our external environment is received by one of our five senses – sight, sound, smell, taste or touch. Sensory receptors pick up this information and then pass it on to the brain. The conduit for this information is the nervous system. This information-delivery system has been created to educate the organism about its environment, helping it distinguish what is helpful or harmful. For example, the sun helps the body create vitamin D, but too much sun exposure may also burn the skin, creating damage that could lead to skin cancer. The nervous system needs to identify when a good thing can transform into a dangerous thing.
The pathway for sensory nerve information works like this: sensory receptor > peripheral nerve > nerve root > spinal cord > brain. The phenomenon of referred pain happens when information from different receptors is passed on to the same peripheral nerve or nerve root. Since all information is transmitted in the form of electrical signals, information from two different receptors converging at the same location of the spinal cord may confuse or even overwhelm the brain, making it difficult to distinguish between the two different signals. If one of the messages is good and the other is bad, the brain may interpret both of them as being harmful.
Consequently, damage to tissues in one area may lead to an interpretation that damage is being done to a completely different set of tissues in another area. The result is a referred pain pattern.
Common Sources of Referred Pain:
Peripheral nerves are nerves that exist outside the spinal cord. Irritation at any point along these nerves creates a burst of electrical signals that arrives at the spinal cord where these nerves attach. Since the resulting barrage of signals at the spinal cord is the same, no matter what part of the nerve is irritated, the brain might register that the whole nerve is affected. This may cause pain to be felt along the entire nerve.
For instance if the piriformis muscle in the buttocks irritates the sciatic nerve in this area, the resulting pain may be felt along the whole sciatic nerve, all the way down the back of the leg to the foot.
The sensory receptors from the ligaments and tendons feed back to the spinal cord. If one of these tissues is overstretched or irritated, the nerve impulses may mimic those from other tissues connected to the same cord level. As an example, nerve information from ligaments surrounding the sacroiliac joint may converge at the spinal cord at the same point as the sciatic nerve. Damage to these ligaments may also resemble a case of sciatica, referring pain down the back of the leg to the knee.
A tight, dysfunctional muscle has a pattern of pain that can be produced when specific points are pressed. These are called trigger points. In some cases, trigger points in most of the gluteal muscles will refer pain down the back of the leg, mimicking a sciatic nerve issue.
Nerves also connect every visceral organ in the body to the spinal cord. Therefore, converging information at the spinal cord may result in referred pain patterns in musculoskeletal tissue that is actually related to an organ problem. One of the most recognizable patterns of organ referred pain is left arm, shoulder or jaw pain that is related to problems with the heart – typically associated with angina and/or heart attacks.
Chiropractic and Referred Pain:
Vertebral subluxations irritate the nervous system at the nerve root and spinal cord level. This will cause the nervous system to be either more or less sensitive to information received at the same level as the subluxation. Chiropractic adjustments can reduce irritation caused by subluxations and help with all sources of referred pain.
Chiropractors are equipped with a number of orthopedic and neurological tests that can distinguish referred pain patterns from more direct causes of pain. Ask your chiropractor if you may be experiencing referred pain.