Intervertebral discs are “spacers” between the spinal bones. They provide room for the joints to move allowing flexbility of the spine. They also provide room for the nerves to exit from the spinal cord to the rest of the body.
Discs are usually filled with water and are quite flexible, almost rubbery. Due to lifting injuries, repeated physical stress, automobile accidents, etc the outer disc fibers (annulus) become damaged allowing water to escape from the disc. In time, the disc become more and more dehydrated and beghins to weaken. Just like a car or bicycle tire that’s sidewall is weak, a bulge forms. The bulge may put pressure within the canal that nerves pass through causing not only back pian, but also butt, thigh, leg or foot pain (sciatica).
The disc bulge may worsen and the outer fibers may actually tear open and allow inner disc material (nucleus) to protrude outward (herniation) into the nerves or spinal cord. In most instances, a herniation like this will cause back pain and sciatica, but also serious physical signs such as loss of muscle strength in the legs, shrinking of leg muscles (atrophy) and/or loss of reflexes. See video tutorial of disc herniation here: http://www.CureForLowerBackPain.com
Diagnosis of disc bulge and herniation are by careful phsyical examination and confirmed conclusively on MRI scan. Plain x-rays will NOT show disc bulges or herniation. A seemingly normal x-ray may show up as a severe herniation on MRI.
