08/11/2025
Great explanation of why you may feel better after you’ve been ‘cracked’.
SPINAL MANIPULATION – WHAT’S REALLY HAPPENING
There’s this ridiculous idea floating around that a simple thrust can “realign” your bones. Let’s be clear — that’s not what’s happening. You cannot push vertebrae back into place with your hands. The spine isn’t dislocating and relocating every time someone cracks your back. If it were actually misaligned the way some claim, you’d be in hospital, not on a treatment table.
When a practitioner performs a spinal manipulation, the movement is extremely small — a few millimetres at most. The joint surfaces briefly separate, creating a rapid change in pressure within the synovial joint. That change causes gas (mostly CO₂ and nitrogen) to form and collapse inside the joint fluid — the audible “pop.” That’s all the noise is. It’s not bones moving back into place. It’s cavitation — a pressure change in the joint capsule.
Physiological Effects
Manipulation affects the body mainly through neurophysiological responses, not through physical repositioning of bones. The quick stretch activates mechanoreceptors within the joint capsule and surrounding tissues. These receptors send a flood of sensory input to the spinal cord and brain. This temporary barrage can reduce the sensitivity of nociceptive pathways (pain signalling) and alter muscle tone via reflex mechanisms. That’s why after a manipulation, patients often feel “looser,” “lighter,” or notice an improved range of motion — it’s not because their bones were realigned; it’s because their nervous system has momentarily adjusted how it’s interpreting movement and pain.
The effect can also increase local blood flow and help restore normal joint motion if it’s been restricted by protective muscle guarding. Again — that’s a functional change, not a structural one.
Why the Realignment Myth Persists
The “realignment” myth continues because it sounds dramatic and easy to sell. It gives people the impression something was out of place and the practitioner fixed it. It’s a neat story — but it’s nonsense. The vertebrae are held in place by strong ligaments, discs, and deep stabilising muscles. A single thrust cannot overcome that structure and magically shift things back.
