There are a few reasons why pain can manifest in other regions of the body when the pain source is not so readily noticeable, with spinal nerves being one of the main causes.
Nerves span nearly all parts of the body in a similar way blood vessels spread all over the body. To recognise sensation in the shoulder we need to connect the sensor in the shoulder with the supercomputer that is our brain. A nerve does exactly that. You can liken it to the electrical wiring you have in your smart phone. The microphone in your phone, which is essentially a sound sensor would be no use unless it was wired to the computer that made sense of the noises and transmitted them to someone else’s phone to be able to hear you speak. Likewise, small nerves in the shoulder need to get their signals back to the brain so it can give us a conscious recognition of feeling in our shoulder.
As our nerves get closer to the spinal cord, (which is essentially a giant collection of nerves) they bundle together and then merge into the spinal cord before travelling to the brain.
At times, there can be issues somewhere along this nerve path. If the wiring is affected, perhaps by a tight neck joint, or a stiff neck muscle, the brain can get confused by signals it receives. The brain may receive a signal from the shoulder which has been somewhat distorted which confuses the brain and is therefore recognised as pain. Basically, it’s just like my old university car, the dodgy wiring of which meant it would show a light on a dash board saying I needed fuel, despite there being a full tank.
If nerves for more than one body part enters the spinal cord at the same point, and those nerves are injured, the brain can become confused by the source. This is what happens with the neck and the shoulder – both nerves enter the spinal cord at the same point, and with injury, the confused brain is likely to think that messages of pain sent from the shoulder is coming from both the neck and the shoulder. This referral of pain is called ‘Somatic referred pain’.
In any patient presenting with shoulder pain, we often assess the neck to rule out any referred pain before providing you with an accurate diagnosis.
If your neck or shoulder is bothering you, come in a Bend + Mend Physio at either our Barangaroo – King Street Wharf or Martin Place clinics.