Doctor Answers (1) on Nuckels break..
Knuckle breaking or cracking knuckles expands the space between your bones, creating negative pressure that draws synovial fluid into the new gap.
This influx of synovial fluid is what causes the popping sound and feeling when you crack a knuckle. If u continually crack ur knuckles, the synovial membrane and the surrounding ligaments will loosen, making it easier and easier for your joints to crack and damage ur ligaments.
Though there is just psychological feel good factor and may help release stress its not beneficial and may b damaging in the long run.
Research doesn't relate cracking knuckles to increase chances of arthritis.
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.
Hope this helps... If u have any more queries please don't hesitate to ask.