The natural curves at the neck and back are lost when the spine bends forward:
- the neck curve (yellow line) is now straight
- the curve at the ribs (orange line) now has a bigger curve
- the low back curve (red line) is now straight
Losing these curves means the spine cannot move easily, and we can get stuck for hours.
There is only a small amount of forward movement to go from the best to the very worst spine posture. In many cases, the spine cannot bend any farther!
When the spine is fully slumped, the joints and muscles are more prone to injury: the muscles can stretch and weaken, and the cartilage and ligaments stretch, and over time they will eventually deform to the new posture
When sustained, this posture is also the causal link to the physiologic diseases associated with leisure sitting.