Spinal Alignment

UNDER CONSTRUCTION

In order to comfortably stand or sit, the centre of gravity of the body needs to lie a little behind the bottom of the spine. In this position, the amount of muscle exertion needed to maintain this posture is minimized. When changes happen to the shape of the spine, either by injury or degeneration, the centre of gravity usually moves forward. When this happens, either the level of muscle exertion must go up, or other parts of the spine must move in the opposite direction to compensate. Both situations (increased muscle exertion or compensatory movement backwards at other levels) can be a cause of pain. Spine surgeons call this situation loss of sagittal alignment. 

The commonest cause of loss of sagittal alignment is disc degeneration. The intervertebral discs are the softer flexible connections between the vertebral bones. In healthy spines, the discs are often wedge-shaped (particularly in the lumbar spine), with the front of the disc taller than the back of the disc. This creates an angle that causes the upper vertebra to bend somewhat backwards (correct term is Lordosis). When this angle is lost, due to disc degeneration, the vertebra angles forward into a position known as kyphosis.