Q: So what positions and moves all those bones in synchrony?
A: Your muscle system.
Q: So what makes your muscles move your joints?
A: Your nerves.
Every muscle in your body is connected to a nerve that feeds back information to your brain about tone and stretch and position. This is how your brain builds up a picture of what is happening to you in space and time. The quality and clarity of this feed back determines the quality and clarity of feed back to the muscles, like a loop or a circuit. The better the feedback the better the movement patterns, efficiency and performance of your muscles, your joints and your body.
Your network of nerves connects to every square centimetre of your body. Every sq. cm. of YOU is connected to a nerve that feeds up to a trunk of nerves that enter the spine in between each vertebra and then the enter the spinal cord and on up to the brain.
That is why Chiropractors focus on how the spine works because we want the connection between you, your nerves and your brain to be as clear as possible. A spine that doesn't work as well as it should can confuse the nerve communication up to the brain and back down again.
The clearer the nerve communication throughout YOU the better you work, the better you heal, the closer you are to your full potential and the less injuries and ware and tear you will accumulate over time.
We are made of many things that are made of many cells but every cell, every organ is connected to the one under your hat (your brain).