Good news, young knuckle joint popper. According to the few medical studies conducted on this habit, you may continue to crack your knuckles and annoy your neighbors without penalty for years to come. To date, there is no proven connection between knuckle cracking and arthritis, except for Dr. Mom's lingering words of warning from childhood. When you crack your knuckles, you are not causing permanent damage to your joints. You're not necessarily doing them any favors, but they will get over it.

When you crack your knuckles, the popping sound you hear is a gas bubble escaping from between your knuckle joints. The knuckle's bones, ligaments and tendons are surrounded by a thick liquid called synovial fluid. Over time, this synovial fluid becomes filled with tiny bubbles of gas. When you push or pull on the joints to crack your knuckles, the tendons and ligaments become stretched out and the knuckle bones separate slightly. When the synovial fluid tries to fill in this gap, the trapped gas bubbles combine to form one large bubble.

This bubble pops in order to make room for the sudden rush of synovial fluid into a capsule between the knuckle joints. When you successfully crack your knuckles, the popping sound is soon followed by a satisfying stretch of the joint and increased mobility. This gaseous build-up is not harmful to the body if it is not released through knuckle cracking. After approximately 25-30 minutes, there should be enough gas built up to crack your knuckles again, if that's what floats your particular boat.

Although medical studies did not prove a link between knuckle cracking and arthritis, there was some evidence that excessive knuckle cracking could cause a loss of grip strength or swelling around the joints. When you crack your knuckles, or any other body joint for that matter, you are subjecting the tendons and bones to unnatural pressure. Over a long period of time, body tissues do not recover from such manipulations as they once did. This can create the same types of joint pain as professional athletes experience after throwing a football or pitching a baseball for years.