The Human Spine - Front & Side Views Each section of the spine has a natural curve. Viewed from the side, the cervical and lumbar spines have a lordotic, or slight concave curve, and the thoracic spine has a kyphotic, or gentle convex curve. Natural curves are important. Without these curves the spine would not have the strength and resilience to act as a shock absorber during movement. The back's curves are designed to absorb shock and to facilitate the full range of motion throughout the spinal column. The natural curves act as a coiled spring to absorb force or jarring during activity. Jogging or jumping rope would be impossible without these curves. The yielding curves are the pillars of strength, resilience, and flexibility in the spine. Nonetheless, our back's flexibility is not without its own set of problems.