Referred (or the very similar term radiating) pain is when the bit that is sore (a nerve, a tendon, a ligament etc.) ‘broadcasts’ the pain to another location away from the cause.
This is a bit weird when you think about it. One explanation for this is that, apart from skin, the pain wiring of a lot of internal structures is not precise enough to reliably localise damage/inflammation to the actual location of the problem. The brain makes a ‘best guess’. Nothing is wrong with the area where the pain is felt.
Think left arm pain with a heart attack, or calf pain from a nasty lumbar nerve root irritation. There are characteristic and useful patterns of referred pain, though they do vary a lot from patient to patient.
It’s worth exploring a couple of ideas about what I call local pain – a term I use to describe pain that is occurring in the area of the grumbling painful structures. This is the opposite of referred pain. A hockey ball hitting your shin bone causes local pain, probably because the bulk of the damage is to superficial structures like the skin and the underlying connective tissue. Quite confusing is that structures like ligaments, tendons, muscles and joints can generate pain locally, particular if there is actual tissue damage (like a muscle tear), but at other times can refer pain to different locations (like a muscle trigger point).
Then there is the special case of the nerve bundles that exit the spinal column. These nerve bundles (which supply sensation and power to the target skin and muscles) have a wrapping around them which is enveloped with small ‘pain’ fibres. So, a nerve has its own nerves! These nerve bundles, when they get sore (and they often do as they exit the spine), can refer and radiate pain down the path of the nerve.
Local pain might have a cause in the area of the pain (like that hockey ball) or the source might be remote. By remote, I mean that a problem somewhere else might be causing a structure to get sore through no fault of that structure – for example, a stiff mid back might trigger a perfectly ok shoulder joint to work awkwardly enough so that the shoulder joint gets sore. This is a somewhat sophisticated insight but is of surprising usefulness when it comes to tracking down the causes of spinal soreness. There are degrees of remoteness. For example, an overloaded and sore muscle might be irritable because a nearby spinal facet joint is stuck, or because something right at the other end of the spine is not working correctly.
As patients, it is only reasonable that you tend to see your pain as being always local in origin. Or, put another way, surely the problem is where the pain is? Often this is wrong and can be very misleading regarding causes. But this patient viewpoint does explain why a practitioner’s focus on other areas of the spine or body can sometimes be disconcerting for the patient!
So, when an osteopath thinks about your pain, he/she asks;
- is the pain local and is the primary cause of it in the same area?
- is the pain local but does the primary cause lie somewhere else?
- or is the pain a referred pain (in which case where is the source)?
Footnote: that term radiating pain is often used to describe a referred pain that is propagating in a wave-like way further from the actual source. This happens when the irritated structure (e.g. an inflamed nerve root) is getting more and more annoyed. The sorer it gets, the further it ’radiates’ (or refers) the discomfort. As the soreness eases, so the ‘broadcasting’ gets closer to the source.