When we move, we can naturally accentuate or reduce the curves in our spine. This is okay to do temporarily, however, we want to try to maintain the natural curves of the spine. In other words, maintaining good posture is is an important goal. This is because the normal spinal curves give the spinal column increased flexibility, enhance the shock absorbing capacity of the spine, and make sure that there is adequate stiffness and stability at each spinal joint, all of which serve to protect the spine and promote proper spinal function. Although the spinal curves perform these important functions, it should be understood that spinal shock absorption, stiffness and stability cannot exist without an intact and functional muscular system.
Muscles act like the guy wires that anchor a tent and give it stability.
Without spinal and abdominal muscles the spine could easily buckle and almost be bent like a pretzel. For this reason, properly exercising both the spinal and abdominal muscles plays an important role in treating and preventing low back pain and injury. Figure 2 illustrates a lumbar vertebra from two views, i.e., from above or superior, and from the side or lateral. From the superior view you can see the two superior facets and the top of the vertebral body. Although you cannot see them in this image, the same vertebra has two inferior facets and a bottom or inferior side of the vertebral body.