It's all about osseus alignment. The chiropractic physician is trained to detect subluxations and dis-articulations of the skeletal system. He would detect these via X-ray, and then use adjustments to correct the defaults. When a bone moves back into place, the nerve, disc, muscle, and ligaments are now allowed to function normally.

You get healthier. It usually takes more than a single adjustment as you have to re educate the muscles which act on the bones.

You generally feel much better, and more aligned.

It depends on the style of adjusting. However, essentially bones/joints that are out of place are put back in place which relieves the pressure on the nervous system that is causing the pain.

Dr. Lesa G. Ansell, DC, APRN, AGNP-C   

The adjustment aligns the joints and improves function to the joints as well as the nerves which come out of the spine.