Is your spine straight, or is it curved? What would you say?
The normal human spine is made up of 26 segments(*) ie. 24 vertebrae, plus 1 sacrum and 1 coccyx, which are the little ones at the bottom. These segments form curves. Yes, curves plural. Four of them, something like this(**)
If you’re wondering what a single vertebra looks like, imagine you buy a salami – one of those big ones that curls right round on itself – and chop it into slices. That, very roughly, is your vertebra. It’s a slice of a tube, but not a nice straight tube. It’s built to fit into a curve.
Now in reality, a vertebra is vastly more complex in shape than our slice of salami. It has dips and depressions, bumps and poky-out bits. In fact, it’s the most beautiful, incredible design, and no two vertebrae are exactly the same. That’s why, when you stack them up, they don’t stack in a neat vertical line. They “stack” in four curves – a shape that makes the spine much stronger.
“Yeah, yeah. 26 segments. 4 curves. So what’s the big deal?” I hear you ask.
This is the big deal. Each of these segments moves, just a little bit. What do you suppose happens when someone is told to sit up straight?
Scary, isn’t it.
They do sit up straight. Absolutely straight. Straight like a wall, or a chair leg or a ruler. And there’s only one way you can achieve that: by brute force. To get a straight spine you have to pull each and every vertebra out of its natural alignment using sheer muscle power.
That’s a lot of work. A lot of unnecessary strain. And a recipe for backache. Forget “straight”. Get reacquainted with your lovely spinal curves.
(*) I’m taking the fused bones of sacrum and coccyx as 1 segment each, and part of the functional spine. Some people count them separately. Either way is fine.
(**) The guy with the big nose is not necessarily drawn to scale