1.   He closed his novel for a moment, straightened his spine and raised his bespectacled gaze to the chalkboard at the front of the hall.

2.   Perched on the ball, the body improves its posture by straightening the spine.

3.   She also needed physical therapy and a brace to help straighten her spine, which was curved backward from her cramped position in the womb.

4.   To reach the pockets, a wearer must thrust his chest forward and shoulders back, thus straightening the spine.

5.   Three surgeons straightened his spine, removed shattered pieces and replaced them, and repaired torn ligaments in his back.