Many people crack their knuckles every once in a while, it’s a common habit which produces a sharp cracking or popping sound. Now, there are many varying opinions about the health effects of cracking your knuckles. For some people, it’s completely harmless and is probably a good habit, while some people claims that cracking knuckles leads to arthritis. But there’s no medical evidence to support that.

The real reason behind the ‘cracking’ sound when you crack your knuckles and it’s long term effect has been the topic of debate for many years in the scientific community.

Now, a team of Canadian and Australian researchers have published a new study that settle the debate on what’s happening inside your fingers when cracking the knuckles. This study was named “Pull My Finger” study by researchers. For this study, researchers have used MRI to video record knuckle cracking in real time.

Below is the MRI video from University of Alberta that shows what is really happening inside the joints when cracking knuckles.

The study found that when we stretch our joints like when cracking a Knuckles, gas-filled cavity is formed within the synovial fluid (lubricant like substance found in between joints). This gas forms a bubble and collapses and pops which makes a ‘cracking’ sound.

cavity

“It’s a little bit like forming a vacuum. 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.” explained the study researcher Greg Kawchuk, a professor in the Faculty of Rehabilitation Medicine at the University of Alberta in Canada.

Here’s the video from Vox that explains what really happens to our knuckles when we crack them.

SO IS CRACKING KNUCKLES REALLY HARMFUL FOR JOINTS?

Scientists have calculated that the amount of force at work when you crack your knuckles has enough energy to cause damage to hard surfaces, yet research also shows that habitual knuckle cracking does not appear to cause long-term harm.