If you're among them, it's likely that the only consequences you'll face for your popping and snapping will be comments from friends and funny looks from innocent bystanders. Chiropractors make a business out of manipulating joints to reduce stress, and dedicated joint-crackers even have their own Web site and discussion board, on which to exchange anecdotes. 'When you move the joint back into position,' Naidu notes, 'the fluid comes under normal pressure again, and the bubbles gradually go back into solution.' The time it takes to re-dissolve the carbon dioxide into the synovial fluid prevents the knuckle from cracking again for a few minutes.Īlthough the actual process of cracking a knuckle may take only a few milliseconds, the relief that some people feel from it is palpable. The stretching of the capsule also allows a temporary increase in the joint's range of motion. The gas then comes out of solution suddenly and forms bubbles, which makes a popping noise.'

'If you pull on the joint or distend the joint capsule,' he notes 'the walls of the capsule expand and lower the pressure on the fluid inside it. But what makes that disconcerting sound? Naidu explains that the cracking noise is caused by a gas, mainly carbon dioxide, that is usually dissolved in the synovial fluid that encapsulates most joints. So your mother's childhood warnings were just old wives' tales.

Anatomically, physiologically, and mechanically, there's no reason it should cause harm.'Įlaborates Naidu, 'You literally have to disrupt the joint capsule through excessive force-like a ligament injury in a knee, or 'skier's thumb,' for example-to cause chronic, long-term damage,' The forces generated by knuckle-cracking are relatively small in comparison. 'It also should not cause joint weakness, on a long-term basis. It does not strain the ligaments or the tissues, or overextend them enough to cause arthritis,' Naidu says. 'Plain old knuckle-cracking should not cause any damage. Does cracking your knuckles cause permanent damage?Īccording to Sanjiv Naidu, Penn State professor of orthopaedics, it does not. And yet maybe it's harmless-you're not really sure. You suspect that it's unhealthy, but it feels so good that you just don't want to stop. Most of the time you get away with it, but sometimes you get caught, and people turn away in disgust. You do it mostly when you're alone, but sometimes you do it in public-under the table in a restaurant. On the arm of your office chair, or right on the desk. You've done it more often than you're willing to admit.

How to crack your thumb