laura2Are you stressed before an application for a job? Or maybe just before an exam? Have you been writing for a long time and you just want to ‘’relax’’ your fingers? – Cracking knuckles is the answer. Everybody has done this process at least once in their lives.  The science of “Cracking knuckles”, has grabbed the attention of many scientist, and it is now known what makes knuckles pop.

Scientists at the University of Alberta used magnetic resonance imaging (MRI) video to determine what happens inside finger joints; more specifically, what causes the distinctive popping sounds heard when cracking knuckles.

The study, called ‘’Pull my finger’’ (don’t worry, it has nothing to do with the embarrassing phrase used by kids) was based on inserting someone’s finger into a tube connected to a cable that slowly pulled his knuckle until the joint cracked. The MRI video captured the results in real time.

Each time, they found that the sound was associated with the rapid creation of a gas-filled cavity within the lubricating fluid surrounding the joint, which remained visible after the noise was produced. In other words, the sound of cracking knuckles comes from bubbles of gas that are formed when the bones stretch apart.

"It's a little bit like forming a vacuum," lead author Kawchuk explained. "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." So the truth is when you are cracking your knuckles, you are not actually cracking anything.  According to Kawchuk, the ability to crack your knuckles could be related to joint health.

This study is very important, not only because could have implications for other joints in the body, but it can also be used to discover joints problem, before the symptoms starts.

Although cracking knuckles seems not to be harmful, it is still an annoying habit for many people. Oh, well, let it be.





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