What happens when you crack your knuckles?!

What happens when you crack your knuckles?

We've all heard the claim that cracking your knuckles will cause permanent injury. But is it really true that a life of arthritis awaits the knuckle-popper addicts among us? Our search on "what makes knuckles crack" led us to a couple of sites that explain what happens when you hear that distinctive pop.
We first stopped by KidzWorld, a great place for kids to find the answers to all sorts of questions. An article titled "Cracking Down on Knuckles" provided a comprehensive answer to your question. When you crack your knuckles, you're essentially pushing the joint into or out of its normal position. A thick, clear lubricant called synovial fluid is found in the joints between your bones. When you crack your fingers, you cause the bones to pull apart, and the pressure on the synovial fluid is reduced. Bubbles form and quickly expand and then burst. Snap, crackle, pop go your knuckles!

Next we stopped by the inestimable How Stuff Works. Marshall Brain corroborated our earlier findings and offered a bit more detail. He explains that the bubble forms in a process called "cavitation." Once you've cracked your knuckle, it takes about 25-30 minutes for the gas to dissolve into the joint fluid. During this time, you can't crack the knuckle again. But once the gas is dissolved, cavitation is once again possible, and you can start popping your knuckles to your hand's content.

Okay, now we know what happens when you crack your knuckles, but are you doing serious damage? We read a bit more and discovered that only one in-depth study of the issue has been published. The study focused on 300 habitual knuckle crackers and found no evidence linking knuckle cracking and arthritis. Chronic crackers did suffer other harm, including soft tissue damage and loss of grip strength. This damage is usually minor, however, and cracking your knuckles actually has some benefits -- you'll feel looser and enjoy more mobility in your joints immediately after popping.