Why Do My Joints “Pop”

What is that popping sound heard when I pop my knuckles our when my chiropractor adjusts my spine or other joints of my body? This is a great question I get asked all the time. Many individuals are concerned by what is causing the noise and others are just curious.

“Cavitation” is the technical term for the sound heard when a joint is manipulated. The sound heard when your chiropractor adjusts your spine is the same as when someone “pops” their knuckles. Okay, so nice fancy name, what is actually happening?

There are several different types of joints within the body. The joints that can be cavitated are synovial joints. These are the most common type of joints within your body. Your finger, knee, elbow, shoulder, and facet joints of your spine are examples of synovial joints. These joints are surrounded by a ligamentous capsule and filled with a lubricating substance called synovial fluid. Nitrogen gas gets mixed in solution with the synovial fluid. This is normal and is not a problem or a reason why your joints become fixated or painful. But this nitrogen gas is the key to the cavitation that occurs with a manipulation.

During a manipulation the joint capsule becomes stretched. When this occurs, the volume of space within the capsule is increased resulting in a sudden decrease in pressure. Remember basic physics. Now, this sudden decrease in pressure causes the nitrogen gases to come out of solution, and “POP”.

So there you have it. The popping sound is not your joints rubbing together and certainly not your bones breaking. Nitrogen gas will return into solution in the synovial fluid within about 20 minutes. This is why you cannot get the popping sound to occur if you try to adjust the same joint again, unless you wait about 20 minutes.

Why Do My Joints “Pop”