The normal curves of the spine are seen is Figure A. There is a slight forward curve of the neck, slight backward curve of the upper back, and slight forward curve of the low back. You will notice that the two front tips of the hip bone are in a vertical line. This indicates that the pelvis is in neutral position. A neutral spine indicates that the muscles are balanced.

Figure B shows an anterior pelvic tilt (the front tips of the hip bone are facing down). This results in flexion at the hip joint and increases the curve of the lower back (called Lordosis).

Lordosis causes tight low back muscles from pulling the pelvis upward in the back; and tight hip flexors from pulling the pelvis down in the front.

This muscle tightness causes weakness in the abdominals which are not strong enough to pull the pelvis up to neutral and the hamstrings (back of thigh) which cannot pull the pelvis down to neutral.

You will also notice in Figure B, that there is an abnormal curve of the upper back. This is known as Kyphosis and is seen more and more will individuals who spend a lot of time sitting at a computer.