This is what really happens to your knuckles when you crack them
I am one of those people who simply cannot resist cracking my knuckles. The satisfaction I got from it is unheralded, and the more people who tell me to stop, the more likely I am to continue doing so.
However, for many people, the sound of cracking knuckles is up there with nails on a chalkboard and styrofoam blocks rubbing together. But, despite this, there is also plenty of people who, like me, are addicted to it.
But what happens to our knuckles when we crack them in frustration? Are we really more likely to get arthritis like we're constantly told as children?
Well, according to Harvard Health Publishing, the rumours are lies and cracking your knuckles doesn't increase the likelihood of arthritis. This result was drawn from several studies which compared the rates of arthritis between those who cracked on the regular and those who chose to refrain from this stomach-churning pastime.
One researcher decided to study himself, with him habitually popping the joints in his left knuckle while leaving his right untouched. He carried on the experiment for six decades (!!) and showed no signs of the increased possibility of arthritis in his left hand.
According to Harvard Health Publishing:
"The “pop” of a cracked knuckle is caused by bubbles bursting in the synovial fluid — the fluid that helps lubricate joints. The bubbles pop when you pull the bones apart, either by stretching the fingers or bending them backwards, creating negative pressure.
"One study’s authors compared the sudden, vibratory energy produced during knuckle cracking to “the forces responsible for the destruction of hydraulic blades and ship propellers.”
That said, according to some studies, the cracking of knuckles can lead to swollen hands and a weakened grip. Not only this, but there have been at least two reports of injuries suffered due to knuckle cracking.
According to the conclusions of one study that was published in Annals of the Rheumatic Diseases:
Although habitual knuckle cracking does not relate to osteoarthritis of the hand, it may relate to decreased hand function. Therefore, habitual knuckle cracking should be discouraged.
Back in 2015, University of Alberta researchers published image-based research which found that the popping noise is due to air bubble formations of synovial fluid surrounding the joints in the knuckle.
Speaking to the Washington Post, Professor Robert D. Boutin discussed the research, which saw 40 patients put under an ultrasound machine.
According to the professor, the team found ‘ultrasonic evidence’ of how pressure changes associated with joint fluid bubbles cause knuckle cracks:
"What we saw was a bright flash on ultrasound, like a firework exploding in the joint, It was quite an unexpected finding. […] I will tell you that we consistently saw the bright ‘flash’ in the joint only after we heard the audible crack."
So there you have it, cracking your knuckles has no detrimental effect on your health - you can tell that to your mom the next time she yells at you for cracking away.