I'm assuming that the majority of you reading this are guilty of a good knuckle crack.
It's extremely satisfying to grab hold of your hand and ring out the best possible crack; and that goes for just about any other bone in the body.
All the tales you were told by teachers and parents saying you'll get arthritis was bullshit, so fear not - keep on cracking.
The act of cracking your joints is simply gas bubbles that have been displaced popping. It's pretty much harmless and is called cavitation - chiropractors use these sort of techniques to help improve movement in backs and necks.
This is what cracking your knuckles looks like under an x-ray image intensifier.
Flexing my knuckles under a fluoroscope.Edit: The device used is also known as an X-ray image intensifier.
According to Dr Rachel Vreeman, there's no actual hard science behind why it's so satisfying. It's basically down to releasing nervous energy.
It's also satisfying in the same way that popping bubble wrap is.
Words by Mark McGowan