Referred Pain: Why pain is not always about its location
Too painful and stiff to move, he walked in with his head slightly off to the side and rigid. He began by telling me that something was off in his shoulder blade area, aggravated from an earlier exercise. He then pointed to the inside border of his shoulder blade and said, “ There’s a knot in my back.”
The “knot” is his back was in a familiar place as he had experienced this in the past. Something he hadn’t considered though, was that the pain in his shoulder blade might have less to do with the shoulder blade or the muscles around that area and more to do with structures further up the kinetic chain; his neck.
Pain is a unique phenomenon. All you need to do is type “Pain” or “Pain Science” in any search engine and you will get a wide variety of results. One of the unique characteristics of pain is that it has the ability to be felt in areas other then where the pain is actually originating. This is often described as referred pain, which can be confusing for those who are experiencing it. The true mechanism behind referred pain is debated but a term often used to describe this event is convergence. The idea of convergence stems from the fact that the nerves that supply information to a specific area, in this case a shoulder blade, converge at the same location in the spine as certain nerve fibers from the neck structures. The specific details of this are a little more complicated but the bottom line is, the body is essentially confused about the true location of the pain. Therefore a neck problem can be felt around the shoulder or a low back issue can be felt on the outside of the calf.
Referred pain is different than when someone is experiencing pain related to nerve irritation or compression. The term Sciatica is commonly used when discussing radiating pain down the back of the leg. Semantics aside, the term is somewhat accurate in that a nerve that travels down the back of the leg may be irritated or may be in some level of distress. The pain experience can be generated anywhere along that nerve tract, hence the confusion of why location doesn’t always give us a clear picture of what is truly going on within the body.
The concept of convergence and referred pain is just one of several reason why it is important to have a thorough examination to explore all possibilities regarding pain, discomfort, or dysfunction. Some ideas of what patients can do to help better understand their condition relates back to recognizing the behaviors and symptoms of the condition. Some conditions will have fairly consistent culprits that will either make the condition better or worse. Often times we call these easing and aggravating factors. It is also helpful to take note of how the condition feels in the morning, specifically if there were any issues with sleep and if there were any changes throughout a normal day. Collectively all of this information will assist you and the clinician in determining what truly may be at fault and how to best address it.
As for the hero of our story, he made it! We did a quick neck exam and determined that is was likely the lower part of his cervical spine referring pain to his shoulder blade. After a short bout of treatment his pain was down significantly and he left with some self at-home treatment techniques that he used to clean up the rest of the symptoms he had over the next several days.
References
- Bogduk, N., Innervation and pain patterns of the cervical spine, in Physical Therapy of the Cervical and Thoracic Spine, R. Grand, Editor. 202, Churchill Livingstone: New York.
- Grieve, G., Referred pain and other clinical features, in Grieve’s Modern Manual Therapy: The Verebral Column, J. Boyling and N. Palastanga, Editors. 1994, Churchill Livingstone: Edinburgh.
- Lundy-Ekman, L., Neuroscience: Fundamentals for Rehabilitation. 1998, Philadelphia: W.B. Saunders.
- Aprill, C., A. Dwyer, and N. Bogduk, Cervical zygapophyseal joint pain patterns II” a clinical evaluation. Spine, 1990. 15(6): p. 458-461.
