Joints sometimes pop, all by themselves. This is something that happens to literally everyone. The most common type of joint popping, by far, is the kind you tend to do yourself. Namely, “cracking your knuckles.”
In the 1970’s, what appeared to be definitive research was published that indicated the popping sound you hear when your joints pop comes from bubbles popping. Fluid built up in your joints gets suddenly released and makes the popping sound.
Unfortunately, it now appears that this is not the case. It turns out that the opposite is true, as demonstrated by new research out of the University of Alberta. Lead researcher Greg Kawchuk describes it this way:
“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 is associated with the sound.”
What’s more interesting is the fact that this theory of what causes the popping sound was originally proposed in the 1940s, but was rejected in preference for the research published three decades later. However, it appears that now we have a firm, definitive answer.
There’s more to be said on the topic, however. Another common myth is that cracking your knuckles can cause arthritis. This is actually not the case. To date, there has never been a research study that offered conclusive evidence, or even a correlation between knuckle cracking and the development of arthritis.
This is not to say that it’s a good idea. There have been scattered, but well-documented cases of chronic knuckle cracking causing an overextension of the ligaments of the hand, and there’s at least one documented case of a teenaged girl who developed knuckle pads, which are firm nodules that can form over certain joints, including the joints in your fingers.
And now you know!