The spine, or backbone, contains intervertebral disc and vertebral bodies. These intervertebral disks are the soft tissue cushion between adjacent vertebrae of the vertebral column. Intervertebral disks work as a shock absorbers of the spine that allow for mobility.

These IV discs are found in the lumbar spine and contribute to normal lumbar Lordosis. As people age, the intervertebral disks begin to wear down (degenerates). As the disc degenerates, the upper spine start to tilt forward and For more details you can visit - https://physio-study.com/flatback-syndrome/