"Your spine is made up of 24 vertebrae and the connection between each forms a joint, or "motion segment", with the vertebra above and the vertebra below. These individual motion segments do not provide the same range of motion as elbows and knees, but they work together to allow for forward and backward bending, side-to-side bending and
Movement at a single motion segment is limited to only a few degrees (focal motion), but since motion segments are stacked on top of each other, considerable movement is possible (global motion). And,
certain parts of the spine allow for more movement than others. For instance, you may have noticed that the bones in your neck provide more motion than those in your lower back."
The Spine and Golf
At Address: On all your normal golf shots at address, from the driver through the wedges, there should be a slight bias of the spine away from the target. And when you allow this bias of the spine to occur, let your head move with your spine, so that it is centered between your shoulders, rather than tilted towards your target shoulder.
The Spine During the Swing: The more body parts your move around while you swing the more your
timing has to be perfect to hit the ball consistency. This is why most instruction tells you to keep the spine fixed so your upper body can just pivot around it, like the wheel turning around its hub---nice and simple. Except that isn't what happens because you're a human being not a wheel and as such, when your body is exposed to the forces of the golf swing, it bends and tilts. And if you try to prevent this from happening, you'll either hurt yourself or hit bad golf shots -- or both.
Research shows that all good players have some bending and tilting of the spine as they swing ..... and so should you but you have to keep it under control.
Spine Movement - Up And Down (Bending): You establish your spine angle at address by bending from your hip joints. How much you bend determines how tilted your swing will be. If you bend just a little from the vertical (say 15 degrees), it will flatten your swing because you'll swing the club more around your body. If
you bend a lot (say 30 degrees), your club will tend to move more up and down causing your swing to be more vertical.
Upright swingers tend to be faders of the golf ball, whereas more horizontal swing arcs tend to draw the
ball. If you're slicing you might experiment with a more upright spine angle at address. If you're hooking the ball, bend more from the hip joints (not the waist---that's a slouch). These aren't hard and fast distinctions but they hold a good deal of the time.
Spinal -- Rebound Through Impact: As you swing through the ball, your arms and club whip past your body at a high rate of speed, a result of your body whirling around your front hip joint. In order to stay balanced while you whirl, your spine must be allowed to tilt away from the target---the correct
reaction to the demands of physics know as "staying behind the ball".
To see what your spine does through the hitting zone, place a strip of tape down the middle of a mirror and assume your address position with your left cheek even with the tape. Now simulate impact by allowing your spine to tilt away from the tape about five degrees. If you've done it correctly, the tape now runs through your left shoulder.
For more see: "The LAWs of the Golf Swing