ted by naming both of their adjacent vertebral bodies (i.e. a lumbar disc is can be identified as L-4 L-5 or L-4,5). The discs are made up of an outer ring of more dense material called the annulus fibrosus. The annulus fibrosus helps to contain the inner gelatinous material called the nucleus pulposes. Upon a stressful movement of the spine, the nucleus pulposes may rupture through the annulus fibrosus posteriorly toward the spinal cord. Pressure upon the spinal cord, which is the origin of nerves throughout the body, can irritate the nerves exiting through lateral spaces between adjacent vertebrae called the invertebral foramen. These nerves travel to the lower extremities cause a dull ache and sometimes numbness or loss of strength. The nerve most commonly affected by a disc herniation is the sciatic nerve. The sciatic nerve originates between the third sacral(S-3), and fourth lumbar(L-5) vertebrae, is formed in the pelvis and exits through the greater sciatic foramen towards the gluteal region. It then travels laterally underneath the piriformis muscle towards the pudendal nerve, then divides travels anteriorly down the leg until it divides near the knee into the politeal and tibial nerves(Shanahan, 1997). A term herniated disc is used synonymously with ruptured or prolapsed discs. They describe a protrusion of the nucleous propulsus through the annulus fibrosus upon the spinal cord. Commonly herd terms such as a slipped or a bulging disc refer to the disc being close to herniation, but still remaining intact. In this case, the nucleus propulsus is contained, however, the contortion can still lead to decreased foraminal space, and sciatic nerve irritation. The symptoms for bulging or slipped discs are similar to those for a herniated disc, but are usually milder and less intense, thus requiring more conservative treatments(Shanahan, 1997). An estimated eighty percent of the population suffers at least one episode...
