The Chemistry of Popping Knuckles

IntroductionCracking your knuckles is often debated on if it impacts your health or not. I have found the chemistry behind cracking joints is all natural bodily functions. I chose to deep a bit deeper into this project because I got in a terrible car accident that weakened my back muscles which made me have instability in my spine, this makes me feel the need to “pop” my spine very consistently. I was very curious as to why your joints crack.

Composition of ...

The main parts affected popping joints is the act of pulling apart the joints and the synovial fluid surrounding the joint as well as its’ components.

Main Chemicals, Compounds, Components

    • How: when joints are pulled apart the synovial fluid forms a bubble and it popping is what makes the actual popping noise you hear.
    • What: the synovial fluid forming bubbles
    • When: joints are separated
    • Why: the fluid contains oxygen, nitrogen and carbon dioxide
    • Where: takes place in all joints that the lubricant synovial fluid takes place.

Chemistry's Role

Chemistry plays a large role in joints releases.The fluid in between joints that traps the air bubbles causing the popping is called synovial fluid. Synovial fluid is made up of hyaluronic acid it’s molecular formula is C14H21NO11. This is the main component of joints popping. Synovial fluid also contains collagenases , proteinases, and lubricin. The second component that most don’t take into account is the gases that are being released when joint cavity is stretched. The gases released is nitrogen, oxygen, as well as carbon.

Background Research

Synovial fluid is created naturally in the body the lubricate in between joints. When the joint cavity is stretched the gases rush in, once cavity returns to its relaxed state bubbles are trapped within the fluid.


About the Author

Madison Mars is a junior at Billings Senior High school. She has a passion for music especially the cello.She is talented in the arts; drawing, pottery painting, crafts, etc. She is very outgoing and adventurous. Outdoors is her calling she enjoys hiking, swimming, rock climbing, and discovering the beauties found in nature. She is also passionate about photography but on the opposite side of the camera she has experience modeling for several photographers. Madi is a dancer, gymnast and a previous cheerleader.