How can it hurt here, yet be coming from somewhere else? The mystery of referred pain!
This is a very common question that I get asked all the time. It is very easy to assume that if you have pain in your foot then you have a problem with your foot but actually you could be wrong. I often get funny looks from a patient when I tell them that their elbow pain is from their neck and I have said this multiple times in our Stoke-on-Trent clinics. I have even seen people who have had shoulder pain and had physio on their shoulder, which didn’t work. So they got a scan and they found something on the scan so they had an injection, which also didn’t work. Next they had surgery, which guess what also didn’t work. Then I assessed them and come out with, “I think it’s your neck”. This usually prompts a funny look from the patient and they then say, “but I’ve had a scan and it found the problem”. Then I explain about how common it is to find abnormal findings on scans and how pain can travel.
For example, Barreto et al (2019) performed MRI scans on people with shoulder pain but only on one side. They compared the scans to the opposite pain free side and found no differences between sides with the only exceptions being a 10% worse injury seen on the scan of the painful shoulder for supraspinatus tendon and glenohumeral osteoarthritis. What this highlights, is that you can have something found on a scan with zero symptoms. This means that pain in a shoulder could be from the neck for example, and the scan would make you believe that it was from the shoulder but maybe it wasn’t.
Bottom line is you need to be careful with interpreting scan in isolation to form an accurate diagnosis.
Another example pain could easily be pain in the foot that could actually be referred from multiple regions in the body and it could even be originating from a nerve root compression in your lower back, such as sciatica.
It is important to know that your internal organs can also refer pain to other parts of your body, which can be misleading but very important to know. For example shoulder pain can actually be coming from your diaphragm, which is innervated by the left and right phrenic nerves. These nerves come from spinal cord levels C3, C4, and C5 and these spinal levels also supply sensation to the shoulder. So shoulder pain can actually be coming from your diaphragm and the same misleading pain signals can come from other organs too. We wouldn’t get very far treating your shoulder when the pain is actually coming from an internal organ!
Here is an obvious one: Heart attack, the pain from your heart can radiate into your arm and even your jaw.
Below is a diagram of visceral (organ) pain referral:
So how does referred pain occur?
Well, truthfully it isn’t fully understood but there are some theories on the subject but all have flaws in their logic:
The Convergent-projection theory:
This theory is very old but makes sense. It was first thought up in the 1800’s, which in itself is pretty amazing. Basically the gist of it is this:
Where nerves get lots of high sensory input, which the skin does, and where nerves get minimal sensory input, which the organs do, they converge at the same place in the spinal cord. The central nervous system expects lots of signals from the skin, but not many from the organs. So when an organ is at fault the high input it generates makes the brain assume that the signals must be coming from the skin, as pain from an organ is unusual. So the skin area supplied by the same spinal level as the organ, will be where the brain assumes the pain is coming from.
You could also use this theory with any internal structure such as cartilage in the knee, intervertebral discs in the spine etc. etc.
This theory suggests that pain will refer into a structure that originated from the same embryonic segment as the pain provoking structure.
Other theories are:
Axon Reflex theory, Convergence-facilitation theory, Hyperexcitabillity theory and the Thalamic convergence theory.
What types of referred pain are there?
Originates from your internal organs
Originates from the other tissues of your body, for example muscle, joint etc.
Originates from the nerves, for example a nerve root compression.
Basically visceral and somatic pain tends to be dull and non-specific and neuropathic pain tends to be sharp, shooting or burning and it will follow a dermatomal pattern.
What does getting referred pain mean?
If the area of referred pain is larger, then this correlates with a more painful origin problem and often denotes that the pain has been there for longer. This is also shown in chronic pain sufferers who tend to get an awful lot of referred pain. This also has something to do with central sensitisation in chronic pain sufferers. Mostly the pain will be on the same side of the body that the problem is coming from but in neuropathic pain, the pain can refer bilaterally if the origin is in the central nervous system. An example of neuropathic or dermatomal pain is sciatica, here is more information on sciatica here:
Here is a diagram of referred neuropathic pain or dermatomal pain:
Here are two diagrams of pain referred from muscle:
The Infraspinatus muscle (one of the Rotator cuff muscles):
The Peroneals (muscle on the side of the shin):
Muscle referred pain tends to come from trigger points or muscle knots. If you press on them, then you can often feel the pain elsewhere as per the diagrams above. If you have pain from muscle it can just be from an overworked muscle and a sports massage can help this but sometimes the muscle might be protecting something underlying so physio or even acupuncture might be needed. Here is more information of trigger points and muscle knots:
Here is a diagram of pain referred from facet joints in the neck:
So pain in your arm doesn’t mean that there is a problem in your arm, nor does it necessarily mean that you have a ‘trapped nerve’ in your neck it could mean you have an issue with an internal organ. So don’t just assume what it is because you never know where it is truly coming from. At Hawkes Physiotherapy this is what we do, we assess you to work out the cause of your pain otherwise you would be treating the wrong problem, which doesn’t work!
The content in this blog article is provided for general information purposes only and is not meant to replace a physiotherapy or medical consultation.