A real pain in the… arm
This blog post is staying in the same area as the past couple of blogs posts, the neck/ head. What happens when you pinch a nerve in your neck? Read more to find out.
Assessing and treating a client with pain going down one of their arms can be interesting. It is hard to see the perspective of the client, because of what I know, anatomically. As soon as I hear a client’s main complaint is pain going down the arm, I immediately think cervical spine (fancy medical words for the neck). One of the questions, I almost always get without fail goes something like this, “why are you looking at my neck when the pain is in my arm”?
I will try to explain the connection between the neck and the arm. The brain turns into the spinal cord and the spinal cord gets broken up into different region, by us humans. In the cervical region, the neck, the spinal cord is quite large. If you think about it, it does make sense. All the nerves for the entire body have to pass through the cervical region to get to the brain. Let me give you a little bit of a sense on how this works.
Sensation and muscle action
When something touches your leg, for example, the nerve that detects that type of sensation fires an impulse along that nerve. The nerve then enters the spinal cord and starts going up to the brain. The nerve passes through the upper regions of the spinal cord into the brain, the brain makes sense of the sensation and realizes that it is just a branch brushing up against your leg. Then the nerve has the impulse travel back down the entire spinal cord, out to the muscles that activate your muscles and get you to move your leg out of the way of any sharp branches.
The nerves from the legs, low back and the thoracic spine have to travel up the spinal cord through the cervical area to reach the brain. That is why the spinal cord in the neck area is large, fibres from the rest of the body have to pass through.
The same thing happens in the arm. When something touches your arm, the sensation goes up the nerve to the neck, the spinal cord, to the brain and the impulse goes down the nerve to the muscles to tell you to move. Now suppose there is some injury to that nerve, what happens? An injury to a nerve can occur anywhere along its pathway. What happens when a nerve gets pinched? The pain that occurs could be local, in the neck, from an acute injury. However, if the nerve gets pinched by a disc or some swelling in the neck slowly starts to slowly pinch the nerve you will not usually get local pain. You will get pain or weird sensations in the distribution of the nerve. Each of the major nerves in the neck has its own ‘signature’, if you will, of pain or decreased sensation if pinched.
One example, I have is of a gentleman that underwent thoracic surgery. The surgeon put the client’s arm in a funny position that stressed the client’s ulnar nerve. The client was in that position for a number of hours. When the client awoke from the anesthesia, he immediately noticed that the inside of his forearm and the 4th (ring) and 5th (little finger) digits were numb. That is distribution of the ulnar nerve. Did I lose you? Say the client touched a staple with the tip of his little finger. That sensation would go up the ulnar nerve, to the spinal cord, to the brain, the impulse would come back down the ulnar nerve and get the muscles of his hand to move out of the way so they do not get stapled. One new thing that I mentioned in that last sentence are that sensation and motor neurons (the ones that cause your muscles to contract and you to move) are contained in the same nerve.
To make things even more complex, it can be singular nerves from the neck can be pinched. For example, there are 8 cervical nerve roots, C1-C8, that leave the spinal cord. The lower nerves, C5-C8,T1, join together and mix up some of the nerve fibres. It is kind of like a cloverleaf on a highway, certain lanes of one road end up leading to another road. That is exactly what happens with these nerves. It is called the brachial plexus. After the brachial plexus, C5-C8, T1, turn into the median nerve, radial nerve, musculocutaneous nerve and the ulnar nerve. Though studies we know that if the C5 nerve is pinched off, in the neck before the brachial plexus, it will give pain/ change in sensation in a certain area of the arm. If it is pinched off after the brachial plexus it could be pinched in the median nerve, for example, which is made up of fibers of the C5, C6, C7 nerves, another way to write this is C5-7. And if the median nerve gets pinched, it can give pain/ change in sensation in a different area of the arm/hand.
This is the reason when a client comes to me talking about a pain or numbness going down their arm, I will always look a their neck for signs that the nerve might be pinched there.
One oddity that occurs, and it is seen in the low back as well, the person may have a lot of pain going down their arm or their leg. The nerve is getting pinched in the neck or the low back. However, there is little to no pain in the neck or the low back. This can make it seem that the physiotherapist is not listening to their client because they are not complaining of neck or back pain but that is where the physiotherapist is doing some of the testing.
If you are unlucky enough to irritate a nerve in your neck, do not take offence that the physiotherapist seems to be ignoring your complaints. As they go about looking at your neck movements and strength, they are actually looking for different signs to figure out which nerve is irritated. Once that is figured out, you are on your way to getting better.
If you have pain or numbness down your arm or leg and you would like to ask a question or book an appointment, please click here to contact New Leaf Physiotherapy.