The muscles, tendons, ligaments and cartilage of the human body all have one primary purpose: to facilitate motion. Sometimes a joint popping sound accompanies motion of the joint. Most of the joints that produce a popping sound are synovial joints. The articulating ends of the bones in these joints are covered in a smooth cartilage and are surrounded in a fluid produced by the joint. This synovial fluid nourishes and lubricates the joint, and reduces friction during movement.
When a joint popping sound occurs there are a few different things that may be happening.
The first is due to a release of gas and change in pressure in the synovial fluid in the joint. As the synovial fluid is produced, so are gasses: oxygen, nitrogen and CO2. These gasses build up to create pressure in the joint. That gas is released when outside pressure is applied to the joint. After popping, the synovial fluid continues lubricating the joint and normal pressure is restored, which is one reason that there is a feeling of relief following the pop.
The second reason you may be hearing a pop is from the sound of the tendons quickly snapping over a joint. As you move your joints through their normal ranges of motion, variable tensions are acting on the tendons. This can cause them to change position. You may hear a snap as it returns to its original position. This is the sound you hear in your knees or ankles when standing up from a chair, or walking up and down stairs. These noises are not uncommon, and are generally no cause for concern unless they are accompanied by pain.
The third reason this joint popping sound might be occurring is if you have arthritis in your joints. Arthritic joints crack and grind each time the joint is moved due to the roughness of the joint surface. These joints have lost the smooth nature of the cartilage so there is friction as the bones glide against one another’s rough surfaces. But, joints are not guaranteed to be painful just because there is arthritis.
What if My Joint Popping Gets Worse?
Chances are that the noise in your joints is probably the same cracking and joint popping that we all experience. There is no strong evidence linking cracking your joints to being the cause of osteoarthritis, but if you feel any unusual pops or feel like your joints are popping too much, come see one of the doctors at F.I.T. for an assessment.