While there are many causes of lower back pain, most cases of low back pain can typically be linked to either a general cause - such as muscle strain - or a specific and diagnosable condition, such as degenerative disc disease or a lumbar herniated disc.

In the US, lower back pain is one of the most common conditions and one of the leading causes of physician visits. In fact, at least four out of five adults will experience it at some point in their lives.

Ironically, the severity of the pain is often unrelated to the extent of physical damage. For example, lower back spasms from a simple back strain can cause excruciating lower back pain that can make it difficult to walk or even stand, whereas a large herniated disc or completely degenerated disc can actually be completely painless.

Types of Low Back Pain

Low back pain is typically classified as either acute or chronic:

•Acute back pain is short term, generally lasting from a few days to a few weeks. Some acute pain syndromes can become more serious if left untreated.
•Chronic back pain is generally defined as pain that persists for more than three months. The pain may be progressive, or may occasionally flare up and then return to a lower level of pain. With chronic pain, the exact cause of the pain can sometimes be difficult to determine

Lower Back Anatomy

The causes of low back pain can be very complex, and there are many structures in the spine that can cause pain. Any of the following parts of spinal anatomy are typical sources of low back pain:

•The large nerve roots in the low back that go to the legs and arms may be irritated
•The smaller nerves that innervate the spine in the low back may be irritated
•The large paired lower back muscles (erector spinae) may be strained
•The bones, ligaments or joints may be damaged
•The intervertebral disc may be damaged

Sometimes there is a neurological component, such as leg or foot weakness or numbness, as well.

It is important to note that many types of low back pain actually have no known anatomical cause; but this doesn't mean that the pain doesn't exist. The patient's pain generator may not be identifiable, but this does not necessarily signify that the pain is all psychosomatic. Actually, an estimated 90% of patients with pain will not have an identifiable cause of their pain.