What causes the noise of an adjustment?
That is a loaded question, because not all adjusting techniques that chiropractors use produce the popping noise we associate with “cracking our knuckles”. Some chiropractic adjusting techniques make no sound at all, but many chiropractors do use techniques that create in many instances the popping sound of a spinal “release”. So what causes the noise? A few years ago the mystery may have been solved. A British research team took X-ray movies of a person “popping” his knuckles and found that gas (carbon dioxide) rushes in to fill a partial vacuum created when the joint surfaces are slightly separated. It is this displacement of joint fluid which some believe to be the cause of the noise.
