Mechanical problems are by far the most common cause of back pain. There are many possible reasons why mechanical pain-in which a specific part of the spine, like a disc, a ligament or a joint, does not work correctly- can occur. As well as, strains, knocks and other accidental injuries, a number of diseases can contribute to, or worse, the mechanical causes of back pain (mentioned in the next section). Remember, underlying disease is not the common cause of back pain. Some of the mechanics of back pain are discussed below.

1. Growing Older

Sometimes, back pain is a natural consequence of the ageing process. As we get older the discs that separate the vertebrae lose their flexibility and shock-absorbing properties and are damaged more easily.

2. Herniated Discs

This is the process by which one of the discs ruptures and its inner core bulges out through the outer layer of ligaments that surround it. This is painful enough in itself, but if the bulge presses on a spinal nerve, the pain may spread to the part of the body that is served by the nerve. Herniated discs are most common in the lower back and most often affect people between the ages of 25 and 45. Only about 1 in 25 people who have pain in their lower back that is caused by a physical problem have a herniated disc.

3. Facet Joint Problems

Like the discs, the facet joints that connect the vertebrae together can wear down, or degenerate, and the two halves of the joint can grate against each other, causing back pain.

4. Spinal Stenosis

Spinal stenosis describes the abnormal narrowing of the spinal canal which then exerts pressure on the spinal cord. Spinal stenosis is usually associated with feelings of weakness or tingling sensations. Another type of stenosis is that of the nerve root canal. This can be linked to the narrowing of the foramina, the space between two vertebrae through which the nerve root passes.