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Crack, crack, crack! Each time you crack your knuckles, does someone – possibly a parent – tell you to cut it out? Maybe, that person has even told you that cracking your knuckles will make them large or worse; it will cause arthritis. But as the pressure in those small joints builds, you can’t help but do it again. Crack, crack, crack! Now, you wonder, why am I not allowed to crack my knuckles? Today, we answer that question, with help from ScienceDaily.
Now, we’re not saying that your parents aren’t always right, but cracking your knuckles might not be as bad for you as you’ve heard.
In a recent study published in PLOS ONE, researchers led by the University of Alberta used MRI video to determine what happens inside finger joints when knuckles crack.
Because he can crack the knuckles on each of his fingers on demand, chiropractor Jerome Fryer, was chosen as the test subject. One at a time, his fingers were inserted into a tube connected to a cable that slowly pulled until the knuckle joint cracked.
According to ScienceDaily, the researchers observed that the cracking and joint separation was associated with the rapid creation of a gas-filled cavity within the synovial fluid, a super-slippery substance that lubricates the joints.
"It's a little bit like forming a vacuum," said, lead author Greg Kawchuk, a professor in the Faculty of Rehabilitation Medicine. "As the joint surfaces suddenly separate, there is no more fluid available to fill the increasing joint volume, so a cavity is created, and that event is what's associated with the sound."
While the amount of force at work when you crack your knuckles has enough energy to cause damage to hard surfaces, research also shows that habitual knuckle cracking does not appear to cause long-term harm.
So it might not make your knuckles large or cause arthritis, but that distinctive “crack, crack, crack” sound can still be bothersome to others. Our suggestion? If you’re going to crack your knuckles, wait until you’re alone.
Looking for more Never Stop Asking "Why?" questions? Catch up on all of the past "Whys" on the blog!
