What causes arm pain?

Spinal nerves carry ‘messages’ (via electrical impulses) to the brain about sensation and they send messages to the muscles and tissues to make them move and function.  The spinal nerves that supply the arms originate in the neck and top of the thoracic spine (C1 – T1).

Like elsewhere in the spine, cervical nerves can be irritated and pressed on by disc prolapses, degenerate discs or stenosis caused by wear and tear. When nerves get pressed on or irritated they send warnings messages to the brain in the form of pain, burning sensation, reduced or altered sensation. Sometimes the irritation of the nerve causes weakness in a certain muscle group (called a ‘myotome’) that is supplied by that nerve. For example irritation of the C6 nerve root usually causing symptoms across the bottom of the neck, radiating over the shoulder tip, medial side of the arm into the thumb.

‘Numbness’ means the nerve is dead and if you were to put a needle into your skin you would not feel it – if you can feel a needle being stuck into you then your sensation is reduced and is not described as being ‘numb’. Although reduced and altered sensation maybe very annoying it is not the same as pain – it is important to distinguish between pain and reduced/altered sensation.

‘Radicular pain’ is a term doctors use to describe pain when it is mainly from a single nerve root. Arm pain may also be referred from the shoulder, however generally this does not go below then elbow and is improved by treating the underlying shoulder pain.

If the spinal cord becomes compressed is can cause Myelopathy.

As in the lumbar spine, the most common cause is a cervical disc prolapse, but other causes include bony spurs called osteophytes, or rare causes such as tumours or infection. Disc prolapses are also called ‘herniated’, ‘slipped’, ‘bulging’ or ‘ruptured’ discs. The size of the disc prolapse is NOT always proportional to the amount of pain or weakness felt. A very small disc prolapse in the wrong place can cause severe pain whereas a large central prolapsed might not cause any symptoms.

So the important thing to remember is, just because you have a disc prolapse does not mean you will have symptoms and it certainly does not necessarily mean you need surgery.

Diagnosis

Mr Hilton always takes a detailed history and performs a neurological examination as the first of any diagnosis process. Imaging is used usually to help confirm, or exclude, a diagnosis and this is generally in the form of weight-bearing X-rays, a MRI scan and occasionally a CT scan .

The important thing to remember is that although you may have a wear and tear or a prolapsed disc, the symptoms need to match your scan. For example, a disc prolapse at C4/5 does not usually cause pain down the back of your arm and into your thumb, first and middle fingers as that is more likely to be coming from the C6/7 level.