MRI Shows What Happens Inside Your Fingers When You Crack Your Knuckles (Video)
Before and after knuckle cracking, Credit: University of Alberta
When we were young, our parents used to tell us not to crack our knuckles because it might cause arthritis or some other unhealthy effects. But when we ask them why, they could not give a scientific explanation. Well, below is a video of MRI that shows what happens when you crack your knuckles.
The study, dubbed as Pull My Finger’ and published at PLOS ONE journal was conducted by an international team of researchers led by the University of Alberta, with Faculty of Rehabilitation Medicine professor Greg Kawchuk as the lead author. The aim is to understand what really happens inside the finger joints during the cracking of knuckles.
According to the press release, the idea to conduct a study started when Nanaimo chiropractor Jerome Fryer discussed it to Kawchuk. Back in 1947, U.K. researchers conducted a related experiment using radiography to view the result, wherein vapor bubble formation was said to be the main reason why finger joints crack.
Apparently, that experiment earned doubts and resulted to another study by another team of scientists in the 1970s. This experiment used the same protocol, but resulted to a more complex theory, in which fingered collapsing bubbles was believed to be the cause of the distinctive sound, and not the formation of a bubble.
There were other succeeding related experiments, but the results were not convincing. This latest experiment is the first one that used MRI (Magnetic Resonance Imaging) to view the result. Interestingly, the subject used in this experiment is none other than Jerome Fryer, who is very good in cracking his knuckles regularly.
“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.” Kawchuk said on the report, with each rack occurring in less than 310 milliseconds, real time.
“Our results offer direct experimental evidence that joint cracking is associated with cavity inception rather than collapse of a pre-existing bubble,” Kawchuk added, suggesting that sounds during knuckle-cracking is due to inflation, which is directly opposite to the earlier theories.
But is there really a negative effect when you crack your knuckles?
“The ability to crack your knuckles could be related to joint health. It may be that we can use this new discovery to see when joint problems begin long before symptoms start, which would give patients and clinicians the possibility of addressing joint problems before they begin.” Kawchuk explained.
In the past, scientists suggest that the effect of knuckle-cracking to the finger joints depend on the amount of force during the process. However, a separate study shows that cracking your knuckles regularly does not have a bad effect in the long run. Kawchuk said his team will conduct a more advance study about this.