I crack my knuckles, my neck, my back, and more joints every day. I've been told for years that I'd get arthritis, but I never believed those who told me. Recently in my Medical Terminology class in school, I was given an assignment to debunk or talk about a medical myth. Since I relate to this myth, I decided to research and submit the truth about cracking your knuckles.
Cracking your knuckles is completely harmless. Most people do it just to have that relieving sensation of "releasing tension". The cracking comes from air bubbles collapsing in the synovial joint fluid. (Synovial joint fluid is the fluid between your joints.)
Knuckle cracking is proven to be harmless with an experiment conducted by a Californian physician. For decades, he only cracked his knuckles on one hand. Periodically, he would take x-rays of both his hands and noticed no changes throughout the experiment.