Cracking your knuckles will give you arthritis when you get older. That’s probably something you’ve heard at least once in your life, likely from your mom, concerned that your fidgeting habit will give you arthritis.
A number of studies have been done over the years to find out the long-term impact of cracking your knuckles. Currently there’s no substantial evidence that shows knuckle cracking leads to arthritis.
So, it’s a myth. Cracking your knuckles does not cause arthritis. (Sorry mom.)
As for the “crack” or “pop” noise you hear after you crack your knuckles, it’s not bad either (although it may annoy the people around you).
To understand what makes the noise, it’s helpful to have a basic understanding of joints.
A joint is the point where two bones attach, giving you the ability to move a body part.
Inside the joint is a small pocket of synovial fluid that surrounds the bones. The fluids helps the bones move back and forth without rubbing together.
When you bend or pull your joints, it creates a gap in between your bones. That gap sucks in synovial fluid. The rush of fluid into the gap is what creates the noise you hear when you crack your knuckles.