Is it actually harmful to crack your joints?

[redbreegull]

I have heard dozens of opinions on this over the years going both ways. Some people claim it causes joint swelling, stress fractures, stiffness, and arthritis, and others claim that is a wives tale and there are no negative effects of cracking your joints. Does anyone here have any medical knowledge one way or the other? I am a chronic joint cracker (back, neck, hands, fingers, whatever will crack) and I need to know if this is going to present a serious problem in later life.

[loser2d]

I saw this in the big urban myth show on MTV and they said that there is nothing harmful about it.

[Eulogy]

a chiropractor-type guy once told me that it can be helpful.

at least, i think that's what he said.

[redbreegull]

I have an aunt who actually is a chiropractor and she said she didn't know

[Richard III]

My joints grind sometimes.

[tcm]

just don't get carried away.

[jigga]

i'm sure wikipedia has something on this!

[I'm Hardcore]

i dont know if it's harmful or not, but its disgusting to listen to

[KrazeeStacee]

All I know about it is gas builds up and that's why you have to crack it. I also heard the arthritis and such is a wives tale...however I'm starting to get this chronic pain in my index finger knuckle that I crack all the time. Whether or not it's related I don't know but I am always cracking my fingers/back/toes/etc.

[Skradgee]

I've become way too good at this over the years...cracking just about every joint in my body.

[jigga]

http://www.livescience.com/health/06...nts_crack.html

Releasing gas

A protective fluid cushions most of the joints in our bodies.

Inside a capsule that safeguards bones connected at a joint, synovial fluid keeps the cartilage, tissues, and muscles lubricated and well nourished. Nutrients float inside the fluid, along with gases, such as oxygen, nitrogen and carbon dioxide.

As you bend your fingers, the joint capsule stretches. To make more room for the stretch, gases release out of the fluid. The pop of your knuckles is the sound of gas as it bubbles out of the fluid, scientists say. Before your knuckle can crack again, the fluid must reabsorb the gas.

More to it

Tendons and ligaments make a loud racket too.

Tendons are like rubber bands stretched over joints that keep muscles attached to bones. Similarly, ligaments extend to connect bones to other bones. Sometimes, tendons and ligaments slide out of their spot at the joint and then quickly snap back into place.

If your knee cracks when you stand up from sitting on the couch, you're likely hearing your tendons and ligaments popping into proper position around your knee's joints.

Arthritic joints not only cause pain, they can creak as well.

Connecting bones loose their smooth cartilage and grow spurs on their edges. The amount of synovial fluid also increases, making the joint feel stiff and sore. [Graphic]

Okay to crack 'em?

Scientists have conducted few studies on whether cracking your knuckles can cause arthritis or otherwise harm your hands.

Some studies suggest that you can snap your knuckles all you wish, and it won't cause osteoarthritis.

However, other studies indicate that around-the-clock cracking may damage the soft tissue around the joints, make your hand swell, and weaken your grip.

This article is part of LiveScience.com's weekly Mystery Monday series

[jigga]

Source of sound
The physical mechanism is as yet unproven, but suggested theories include:

Cavitation within the joint—small cavities of partial vacuum form in the fluid then rapidly collapse, producing a sharp sound. This explains the popping that can occur in any joint, such as during spinal manipulation. Synovial fluid cavitation is the most likely theory and substantial evidence exists in support of it. (Discussed in detail below.) [3]
Rapid stretching of ligaments.
Adhesions being broken, which simply means that as two cartilage surfaces are pressed together, they form adhesions, and when the joints are separated this makes the popping or cracking sound.
Of these theories perhaps the most popular is cavitation. When a manipulation is performed, the applied force separates the articular surfaces of a fully encapsulated synovial joint, which in turn creates a reduction in pressure within the joint cavity. In this low pressure environment, some of the gases that are dissolved in the synovial fluid (which are naturally found in all bodily fluids) leave the solution creating a bubble or cavity, which rapidly collapses upon itself, resulting in a "clicking" sound. This process is known as cavitation. The contents of the resultant gas bubble are thought to be mainly carbon dioxide.[4] The effects of this process will remain for a period of time known as the "refractory period", which can range from a few minutes to some hours while it is slowly reabsorbed back into the synovial fluid. There is some evidence that ligament laxity may be associated with an increased tendency to cavitate.[5]


[edit] Repercussions
A single event is not enough to cause damage to the joint, although there is a hypothesis that prolonged joint stress due to cracking knuckles may eventually lead to a higher risk of joint damage. However, the long-term consequences of this practice have not been studied thoroughly, and the scientific evidence is inconclusive. Dr. Donald L. Unger spent fifty years cracking the knuckles of only his left hand twice daily. After this time his hands were found to have no noticable differences and no arthritis had developed.[6] The common parental advice "cracking your knuckles gives you arthritis" is not supported by any evidence, but habitual knuckle crackers are more likely to have hand swelling and lower grip strength.[7]


[edit] References
What makes your knuckles pop?. HowStuffWorks. Retrieved on 2006-09-08.

[topleybird]

Dr. Donald L. Unger: taking a bullet for science for fifty years

I salute you, Dr. Badass Unger