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”

What Does a Chiropractor Do?

What exactly does a chiropractor do? This is a great question. I love answering it and love correcting old explanations my patients picked up from other/older chiropractors. The most common answers I hear from individuals are "you straighten my spine" or "you put my bones back into alignment". While there is some truth to these answers, I don't like them because they impart a false understanding.

The truth is, chiropractors do not take your vertebra or any bone from point A and move it to point B and it stays there. Many individuals believe they walk into the chiropractor’s office with their vertebra "out of alignment" in position A, and walk out of the office with their "spine aligned" in position B. This does not happen.

So what does happen? Chiropractic adjustments/manipulations are about improving the function of your joints, whether it is the joints between the vertebrae of your spine or the joints of your elbow. You walk into your chiropractor’s office with your joints fixated and locked up. They are not moving optimally or with full range of motion. Now you get your adjustment and this frees up or removes the fixation. So now you walk out of the chiropractor’s office with your joints moving more optimally and with the fixations removed.

Some of you may be arguing that you know your chiropractor has “moved your bones” because you have seen x-rays of your spine after treatment and you can see the changes that were made. I am in agreement with you that this can and does occur, as I have seen it in many of my patients. This straightening or improved alignment is happening because the joints are functioning better. The spine was misaligned in the first place because your vertebra was fixated and locked in an abnormal position. Once the adjustment removed this fixation the joint was able to move freely and “sit” in a more normal alignment.

What explanations of what a chiropractor does have you heard?

What Does a Chiropractor Do?