The chiropractor will feel that the bone is out of place, as well as testing the joint springiness. The temperature change in the back also indicates if there’s inflammation. This is caused by a misaligned bone putting pressure on the nerve. Inflammation brings extra blood flow and the temperature goes up.
A chiropractor can use x-rays to clearly see which vertebrae are misaligned. Dr. Ryan Dopps uses x-rays to give specific, scientific data. He also uses a NeuroTherm Scanner that detects temperature changes. This can be safely and gently used on children to avoid x-rays. See the video below for more details.