Lower back pain is not due to the pressure on a nerve root, as lower extremity pain is. Most low back pain is muscular or mechanical in nature, caused by overexertion, overuse, strain or sprain of the ligaments and tendons of the low back. It may also be attributed to degeneration of the disk space and facet joints, which hold the spine together. It may be caused, additionally, by arthritis or stenosis or referred symptoms from organ involvement (bladder, gall bladder, kidney, prostate). One must also rule out organic causes as any form of cancer, especially prostrate CA.

Lower extremity (leg) pain is often seen to radiate, termed "radicular pain." Patients like to use the term "Sciatica". This refers to pain which shoots down the leg from the low back or buttock. It usually results from pressure on a nerve, which produces a pinching of the nerve, which appears to radiate down the leg in the distribution of the nerve pattern. When the "pinching" of the nerve is mild, one may experience numbness or tingling. As it progresses and becomes more severe, pain may develop. Further progression may present actual damage to the nerve, and weakness may also result. This is a more serious form of low back pain, as the distribution of the lumbar nerves supply every organ and function to the lower half of the body. In severe cases, the loss of bowel and sexual function and control can occur. This is deemed an immediate medical emergency. If not treated immediately, long term dysfunction can occur.