What is that ‘pop’ sound

Spinal manipulation is a commonly used technique used by osteopaths and chiropractors as part of a treatment. Often when it is done it can result in a ‘pop’ sound.  This can be a little intimidating, so what is it?

There are various theories and evidence as to what causes it but it must be pointed out that if it doesn’t ‘pop’ then it does not mean it hasn’t worked!

Synovial Joint

The main theory is that when a joint is manipulated there is a reduction in pressure within the joint or articular capsule. The synovial fluid within that capsule naturally has gases dissolved within it. When this is subjected to reduced pressure, that gas forms a small bubble, or bubbles which form a gas cavity – creating a ‘pop’ sound, as the energy is released. Over the next 20-30 minutes the gas is reabsorbed and the joint fluid goes back to normal.

Ref: Carol Fawkes, Research Officer, National Council for Osteopathic Research Audible sounds associated with spinal manipulation – a brief summary of current evidence.