Dear Matthew Alice, What's the lowdown on knuckle cracking? Is it good or bad for you? Are my knuckles getting bigger every time I crack? Am I going to get arthritis because of it? Are my fingers going to fall off? And finally, do I crack my knuckles constantly because I’m a nervous wreck? Everyone says I must be nervous, but I think I do it because it feels good. — Martin Cole, San Diego
There’s a special spot in the Matthew Alice Perfect World for knuckle crackers. It’s in an endless movie ticket line, right in front of someone snapping chewing gum. And much as I personally might like to say, yes, as punishment for that irritating bit of self-indulgence, your fingers will blow up like Polish sausages, probably the biggest risk you run is being left alone and friendless when your loved ones have finally had enough of that aggravating habit. But I digress.
Your question has plagued mankind down through the years. Apparently tired of saying, “Who knows? Who cares?” to patients each time one asked, some physicians actually studied the situation and reported that the noise that makes people’s teeth itch, worse than fingernails on a blackboard, is caused by the bursting of gas bubbles in the lubricating system in your joints. To keep the ends of your fingerbones from wearing out through friction, nature has inserted between the two surfaces a sac filled with a thick fluid, a sort of digital 30-weight, if you will. This so-called synovial fluid contains microscopic air bubbles. When your fingers are stretched out straight, there’s enough pressure on the fluid to keep the bubbles small. When you bend your fingers, you reduce the pressure, the bubbles mass together into a single large bubble, which eventually bursts with a loud snap.
Will knuckle cracking cause arthritis? No evidence to suggest that. Is it good for you? Get serious. Is it bad for you? Worse for the rest of us who have to listen to it. Are you nervous? Probably so, what with all those threats from people around you who want you to knock it off.