Scientists from the University of California brought knuckle crackers everywhere some good news, as they attempted to figure out what exactly happens when you crack your knuckles. Even though the results the results were inconclusive, the scientists agree on one thing: It’s safe to crack your knuckles!
- The debate for what causes knuckles to crack has been going on since 1971
- Ultrasounds have the ability to register events 10 times smaller than an MRI can
- Scientists agree that knuckle cracking is related to a bubble in the joint’s synovial fluid, however they disagree on the exact cause
This spring, a team of scientists published a paper in which they detailed how they used an MRI machine to record what happens when you crack a knuckle, and the results confirmed the theory stating that the cause was a bubble of air collapsing in the joint’s synovial fluid.
However, realizing that ultrasound machines can pick up events a lot better than MRI machines can, a different team from the University of California, led by Dr. Robert D. Boutin, performed their own study.
The team gathered 40 subjects, 30 of whom were regular knuckle poppers, admitting to cracking their joints over ten times a day, every day. The other ten did not crack their knuckles.
The participants were asked to pop the knuckle at the base of each of their fingers, the knuckles known as metacarpophalangeal joints. After recording the participants’ exploits through an ultrasound machine, the researchers investigated the recordings. The results turned out to be more explosive than they believed.
As it turns out, the ultrasound picked up a mini explosion at the joint level, with bright flashes of light accompanying each cracked knuckle, like a firework had gone off inside the finger.
Up to this point, the theories linking knuckle cracking to air bubbles in the joint’s synovial fluid were simply that, theories, however after this experiment, the researchers behind it are certain that the cracking is related to a gas bubble in the joint.
Asked if they were able to determine which one of the two theories was right, if the cracking appeared when the bubble was formed or when it was popped, the lead researcher claimed that it was a very difficult question to answer, however, as some evidence shows, it might be the former.
What they were able to determine without a doubt was that joints showed an increase in mobility after being popped. Not only that, but there were no discernible differences between the group of 30 who were regular crackers and the other 10, who did not practice the habit.
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