What Really Happens When You Crack Your Knuckles



As you age, your body changes. You may have noticed that your muscles start to cramp, your joints start to ache and you hear ‘popping’ noises when you walk up and down stairs.But do you know what’s actually happening to your body when you crack your knuckles?

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Your joints, including those in your knuckles, are surrounded by a membrane called the synovial membrane, which forms a capsule around the ends of your bones. Inside this membrane is synovial fluid, which acts as a lubricant and shock absorber so your bones don’t grind together when you move.

When you “crack” your knuckles, or any other joint, it expands the space between your bones, creating negative pressure that draws synovial fluid into the new gap.

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This influx of synovial fluid is what causes the popping sound and feeling when you crack a knuckle.


If you continually crack your knuckles, the synovial membrane and the surrounding ligaments will loosen, making it easier and easier for your joints to crack.

Are There Benefits to Cracking Your Knuckles?

When you crack your knuckles, the joints become looser and have more mobility for a short period afterward. This perceived positive feeling may be why some people become habitual knuckle crackers.

Ultimately, there are no significant benefits to cracking your knuckles, and a possibility that it could cause injury or damage to your joints and ligaments over time, so this is one habit that you’re better off without.