What Makes Your Knuckles Pop?

Are you a knuckle-cracker?

I am, and it’s an annoying habit. Not only for myself, but for others around me that have to listen to that popping sound throughout the day.

But is it dangerous, or harmful? Will I get arthritis? Will my knuckles deform and swell, until they’re unrecognizable?

The answer is no. Thankfully the practice of knuckle-cracking isn’t harmful. The truth is that when you crack your knuckles, you aren’t actually cracking your bones. Instead the noise comes from Synovial fluid. As that fluid expands it creates tiny bubbles between your joints. When you flex your fingers, cracking them, those bubbles pop.

Here’s a more scientific explanation, thanks to Discovery.


  1. I can’t do it and I have been telling people it is bad for you if you do it now I just have to send this to my friends and see what they think of it. 🙂

  2. Everyone, like teachers, told me I would get arthritis if I cracked my knuckles. But, I knew that wasn’t true. 🙂

  3. My mom used to say that it could cause stiffness in joints (arthritis) if I did it, can’t wait until she sees this video:)

  4. I have a question… If you travel faster than light, would gravity still be applicable? Kind of unrelated, but I just started musing over different possibilities.

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