Our parents have always told us that if we keep cracking our knuckles we'll get arthritis. Is this actually true, or did they just tell us this because they were tired of hearing it? If it's not true, what does actually happen when we crack our knuckles?

As you'll see in the video below from Vox, what you're actually doing is popping gas bubbles that form in the Synovial fluid of your joints.

Will it cause arthritis? It doesn't seem likely. One man cracked his knuckles in only one hand for 60 years and not the other as you'll see in the video. He found no difference between his two hands.

So, crack away if that's what you're into...