The natural shape of the spine is a long S type curve that best absorbs shock from everyday living.
The neck (cervical spine) has a slight forward curve; the upper spine (thoracic) has a long moderate backward curve; and the lower spine (lumbar) has a slight forward curve to it. What happens is that these curves become excessive or minimal through poor postural habits and movement patterns in life. For most people the S curve deviates in a number of common ways: the spine becomes a rounded C curve (rounded back, rounded shoulders), an exaggerated S curve (Sway back, the upper spine has an excessive back curve, and the lower spiine has an excessive forward curve),
Two pervasive symptoms of bad posture are rounded shoulders and a rounded lower back.
What causes this is the sedentary nature of our lives: two main culprits are staring at a computer screen and driving your car. Sit up straight people! Whether sitting or standing feel neutral posture