What are the different causes of back pain?

There are many causes of low back pain. In many cases, the cause is unknown even after full evaluation. When a cause can be identified, some of the most common causes are:

•    trauma – injuries to bones can lead to fracture; muscle injury, strain and tears are also common and may lead to muscle spasm
•    disc disease – when a one or more discs bulges out of its normal location between spinal bones; also called a herniated disc or “slipped disc”
•    osteoarthritis (also called degenerative joint disease)
•    scoliosis – this is curvature of the spine and may begin in childhood or develop much later
•    spinal stenosis – narrowing of the spinal canal, where the spinal cord is located
•    nerve compression or irritation – this may complicate any of the conditions above
Dangerous conditions, such as infection or tumor, are much rarer causes of back pain.
In many cases, low back pain is not caused by a single cause; instead, 2 or more of the conditions noted above contribute to symptoms.