What is the Cracking/Popping Sound?

One of the most frequently asked questions we get in practice is “What is the crack/popping sound?”. Even if a patient does not ask this, it is always one of the first things we explain as there is a big general misconception that it is ‘bones breaking’ for example. Most people have heard this ‘crack’ sound before whether it is when they have arched back or extending/pulling the knuckles etc. So today we are going to clear up this myth for you.

What is it exactly…it is GAS . Each of our joints is tightly bound by ligaments making an airtight capsule around each joint. When the articular surfaces of a joint are separated (still within their natural range of traction), there is a large reduction in pressure as compared to atmospheric pressure. This causes gases to escape from the synovial fluid within the joint forming a bubble; a momentary vacuum. Synovial fluid is the substance that provides for a friction free surface and nourishes the joint. The contents of this vacuum are water vapour, nitrogen, oxygen, and carbon dioxide. The bubble quickly collapses causing the ‘crack/pop’ sound. It is similar to when you open a can of soft drink, there is a build up of gas within the can and when you open it the gases are released making a popping noise.

Chiropractors are highly trained and know all too well the real force required to injure a joint. It would take an incredible amount of force to disrupt a spinal joint due to the incredible strength of the ligaments and muscles that bind the joints together. Spines are NOT fragile.

So be rest assured there is no cracking of bones occurring during a spinal adjustment/manipulation.