Popping your knuckles?
It can make people around you cringe, but cracking your knuckles may not be bad for you after all. Researchers used an MRI video to see exactly what happens when you pop your knuckles. It turns out that pulling the joints apart draws gas into the space. The gas expands and mixes with the synovial fluid, which lubricates your joints, until it builds up so much that it pops, creating the ‘crack’ sound. (All this happens in milliseconds.) Rather than being harmful, the study authors suspect, the ability to pop your knuckles may actually be related to joint health. Tell that to the next friend who gives you a hard time.