Neck pain is a common problem. And the pain from your neck often spreads to the shoulder region or down the arm.

One of the jobs of your head is to support your neck and to allow it to move freely.

Seven bones called vertebrae act as the struts in your neck and these bones are buffered and cushioned by discs of which sit between them. They are held stable with with ligaments and surrounded by muscles that help to give extra support and to facilitate movement.

The very fact that your neck has such mobility is one of the reasons that you experience neck pain so often.

There are lots of possible causes for neck and shoulder pain but among the most common are injury due to trauma, poor posture conditions - sometimes related to work and degenerative diseases, such as arthritis, or wear and tear.

The joints at the back of the neck (near the skin) are probably the single commonest causes of neck pain.

They are called the facet joints or sometimes the “ZA joints” in medical textbooks.

The shoulder is a ball and socket joint with a large range of movement. Once again, a mobile joint tends to be more susceptible to injury.

The design of the shoulder means that the ball is vulnerable to excess movement in the socket so the shoulder joint relies heavily on the shoulder muscles for stability. Any dysfunction, tear or weakness of these muscles or other anatomical structures such as the collar bone, shoulder blade or joint itself can cause pain and mobility problems.

Why do neck and shoulder pain occur together? This is a question that is often asked because one might provoke the other - or vice versa. Many people start off with neck pain and find that it spreads to the shoulder - probably the most common circumstance. Others find the opposite. If the pain starts in the shoulder and then goes to the neck it might well indicate that muscle spasm is an issue.

The neck and the shoulder regions are very closely related - both in their anatomy and in their function.

Neck and shoulder pain can co-exist with each other and it is common to have a mixed pattern of both neck and shoulder pain at the same time. This makes it difficult for you the sufferer to figure out what is going on – but it’s also very difficult for a doctor or therapist to fully get to the bottom of your symptoms if you are experiencing neck and shoulder pain and are looking for treatment.

All of the tissues that make up your shoulder come from the same development area of the growing embryo - the fifth neck segment. This is why pains and problems in both the neck and shoulder are so commonly seen together – the two areas in the body share a common embryo origin.

Pain from any of these embryonic "shoulder bits" is felt in the same part of the arm - and at times all the way to the wrist.

The nerves from the fifth neck segment (sometimes called cervical five – or C5 for short) supply a certain and predictable bit of skin on your arm. This skin area runs down from the shoulder on the outer part of your arm, over the elbow and towards the base of the thumb. Doctors call a skin segment like this a “dermatome”.

Pain from the bones or joints or discs of the fifth neck segment is felt in the same area.

These common embryo origins and shared nerve connections explain why it can be difficult to work out if neck and shoulder pain is arising in the neck or in the shoulder - as far as the brain is concerned, these body areas are very closely related.

Pain in the fifth cervical nerve bit of skin - often called the C5 segment or C5 dermatome - can arise from the neck or from any of the shoulder anatomy

How to diagnose Neck and Shoulder Pain

In most cases the attempt at a diagnosis of your symptoms will begin with your doctor or therapist listening carefully to the story of your neck and shoulder pain - this is often the best and the easiest way to get to the bottom of things for you.

It's often difficult to decide if this kind of pain is arising from the neck or from the shoulder so your doctor will make a close and detailed examination of both areas. The neck first typically and then the shoulder too. Examination of the neck also requires a nerve or neurological (neuro) exam.

Remember that other areas of the body can also send pain to the neck area or the shoulder area so you may also need an examination of the chest or the abdomen.

Sometimes your doctor might take blood tests set up cardiac tests, abdominal tests or respiratory system tests to check over the other areas of your body for you.

It's important to check out the nervous system. The nerves from the neck pass through the shoulder region on the way down the arm and nerve pain from the neck to the shoulder is not uncommon. Other tissues in the neck such as the joints, bones, ligaments, discs and muscle can also send pains downward into the shoulder area.

Remember - neck and shoulder pain can be caused by serious underlying disease. These are rare but if you develop sudden severe pain in this area then seek medical attention as soon as possible.

It is sometimes necessary for the doctor to exclude other problems by performing blood tests or by arranging x-rays or scans.

An x-ray of the neck might show the wear and tear changes of cervical spondylosis. An x-ray of the shoulder might show calcium in the tendons or wear and tear in the shoulder joint.

Sometimes MRI scan of the neck is required to work out why you are experiencing your neck and shoulder pain. MRI scans can show incredibly detailed pictures of the inner anatomy of your body.