Is Cracking Your Knuckles Really Bad for You?

X-ray of hand and finger joints. (Image: Nevit Dilmen/Wikimedia Commons)
X-ray of hand and finger joints. (Image: Nevit Dilmen/Wikimedia Commons)

Cracking your knuckles feels good to some people, but you’ve probably have been told that it will give you arthritis. But is cracking your knuckles as bad as people say?

Here is a quick anatomy lesson: Many of your joints—including those that allow your fingers to beckon or point—feature small pockets or gaps that are filled with synovial fluid.

Like axle grease, this fluid allows the bones that commingle in your joints to glide close to one another without grating, explained Dr. Pedro Beredjiklian, chief of hand and wrist surgery at Philadelphia’s Rothman Institute, to Time

A video on what happens to your knuckles when you crack them:

When you pull, twist, or otherwise “crack” a joint, you’re expanding the volume of space between your bones, Dr. Beredjiklian says.

That volume expansion creates negative pressure, which sucks the synovial fluid into the newly created space. This sudden inflow of fluid is the popping you feel and hear when you crack a knuckle, he added.

Not all doctors agree. This video by Dr. Lee Pierce explains why:

“Finger cracking is so common you would expect to see a lot of causal reports if it was harmful,” Dr. Beredjiklian says. “But you don’t. So I think it’s unlikely cracking joints in hands leads to arthritis.”

A study was published in the Journal of the American Board of Family Medicine, which said that it “represents the most comprehensive evaluation to date of habitual knuckle-cracking and any association with hand osteoarthritis.”

In this video, a doctor from the Trident Medical Center says there is no  harm:

The researchers found that knuckle-cracking is not associated with hand osteoarthritis.

But they do not know what “effect it has on the joint long term.” There are reports of joint damage after vigorous knuckle-cracking, but the reports are not common.

While knuckle cracking seems like it won’t cause you harm, it will still annoy the people around you.

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