Causes

Causes of Herniated Disc

A true herniated nucleus pulposus is most common in young and middle-aged adults. It rarely occurs in children. Degenerative changes in the spine that occur with aging actually make it less likely to develop a true herniated disc. This is because the nucleus in the middle of the disc dries out, making it less likely to squeeze out of the disc.

Discs can rupture suddenly because of too much pressure all at once. For example, falling from a ladder and landing in a sitting position can cause a great amount of force through the spine. If the force is strong enough, either a vertebra can break or a disc can rupture. Bending places high forces on the discs between each vertebra. If you bend and try to lift something that is too heavy, the force can cause a disc to rupture.

Discs can also rupture from a small amount of force, usually due to weakening of the annulus from repeated injuries that add up over time. As the annulus becomes weaker, at some point lifting or bending causes too much pressure across the disc. The weakened disc ruptures while doing something that five years earlier would not have caused a problem. This is due to the effects of aging on the spine-the most common reason for a disc herniation in the lumbar spine.

A herniated disc causes problems in two ways. First, the material that has ruptured into the spinal canal from the nucleus pulposus can cause pressure on the nerves in the spinal canal. There is also some evidence that the nucleus pulposus material causes a chemical irritation of the nerve roots. Both the pressure on the nerve root and the chemical irritation can lead to problems with how the nerve root functions. The combination of the two can cause pain, weakness, and numbness in the area of the body to which the nerve supplies sensation.