The true spinal cord ends at approximately the L1 level, where it divides into many different nerve roots that travel to the lower body and legs. This collection of nerve roots is called the "cauda equina," which means horse's tail and describes the continuation of the nerve roots at the end of the spinal cord.

Vertebrae - The vertebral body is a thin ring of dense cortical bone. The vertebral body is shaped like an hourglass, thinner in the center with thicker ends. Outer cortical bone extends above and below the superior and inferior ends of the vertebrae to form rims. The superior and inferior endplates are contained within these rims of bone.

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Spine surgery is infrequently a preliminary treatment for back pain, however, there are a small amount of emergencies that may require surgical treatment. In the vast majority of patients, spine surgery is only considered behind a long route of conservative therapy. As stated earlier, back pain often takes quite some time to resolve. Therefore, rushing into spine surgery may not be the best idea.

The sacrum is inserted approximating a wedge between the two iliac or pelvis bones and is held together by the two sacroiliac joints. Many back problems occur where the lumbar and sacral region of the spine connect because this region of the spine is subjected to a large amount of stress with certain activities.
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Sacral Ala
Sacroiliac Jointst