The spine connects your muscles, bones and joints. Proper alignment is critical to optimal range of motion and flexibility. It can help you avoid injuries and pain to your soft tissues. Most important of all, it protects your nervous system. The nerves from the spinal cord go through the spinal vertebrae and allows for communication among the brain, cells, tissues and organs.
At it's best, it allows your body to function. When it is damaged or misaligned, it interferes with communication throughout your nervous system and can be painful or cause illness. These damages can be caused over time as well as immediately (for instance, from a car accident).