What Happens to Your Knuckles When You Crack Them

Most of us have, whether by accident or on purpose, cracked our knuckles before. If not your knuckles, maybe you’ve cracked your wrists, ankles, back, or even your neck before. Some of us are serial crackers, while others get creeped out by the noise and feeling all together. No matter how frequently (or how purposefully) you crack your joints, do you know what’s actually happening in your body?

The popping or cracking sound coming from your knuckles is basically caused by the synovial fluid that’s in between your joint. This lubricant substance needs to be released every now and again for your joints to feel loose and comfortable; when you don’t have synovial fluid on the joints, that’s when stiffness can occur.

When you stretch your joint – like when you crack your knuckles, for instance – you’re creating space in the fluid, which in turn causes bubbles to form. The bubbles then collapse and pop, causing the noise you recognize.


To regain bubbles for popping in the synovial fluid, you have to wait at least 20 minutes. So cracking the same knuckle every five minutes? Not going to be as effective as you would think.

What about when you stand too quickly and you hear your knees pop? Or you lift your leg to climb over something and you hear a crack come from your hip joints? (That happens to me constantly.) Well, that’s most likely just the sound of tendons sliding between joints or over muscles.

So is this a harmful thing, cracking these joints to pop these fluid bubbles, purposefully or not?

No, cracking your knuckles isn’t a dangerous practice.


Many studies have backed up this assertion, as well as a 60-year-long experiment performed by self-described “researcher,” Donald L. Uger. For six decades, this dedicated man only cracked the knuckles on one of his hands, while he never cracked the other. He did this to see if one hand would develop more arthritis than the other.

After 60 years and a lot of one-sided cracking, Uger had the same amount of arthritis in both hands, essentially proving that cracking (or choosing not to crack) doesn’t effect your joints negatively or positively, really.

While most studies would agree with Uger’s findings, there is one contradiction. A 1990 study by Jorge Castellanos and David Axelrod called Annuals of the Rheumatic Diseases found that frequent knuckle cracking can lead to hand swelling and a decrease in knuckle function. No studies have been released to back-up these assertions, however.

On the whole, the practice has been established a moot point: not overly bad but not overly good, either. So crackers, keep cracking, if you please.

If you really want to go all-out, you could even go to a professional cracker. What is that, you ask? It’s exactly as it sounds! Someone who professionally cracks your joints in just the right way so it is most beneficial and the least harmful to your body. Not going to lie that sounds amazing.

What do you think about these findings? Do you crack your knuckles often? Are you afraid of cracked knuckles? Share your thoughts in the comments section below.