why is it that everytime you bend down low enough, your knees make a popping noise? (similar to the cracking of knuckles)
122453
I read somewhere that this "popping" is the escape of nitrogen gas. I'd have to try to remember where I read that, though, so I could provide the source.\n\n(EDIT: OK, the below link somewhat verifies what I read, and I'm starting to think I read the "nitrogen" thing here on "nswers" somewhere.)\n\n>>Your joints can make a variety of sounds: popping, cracking, grinding, and snapping. The joints that "crack" are the knuckles, knees, ankles, back, and neck. There are different reasons why these joints "sound off". \n\nEscaping gases: Scientists explain that synovial fluid present in your joints acts as a lubricant. The fluid contains the gases oxygen, nitrogen, and carbon dioxide. When you pop or crack a joint, you stretch the joint capsule. Gas is rapidly released, which forms bubbles. In order to crack the same knuckle again, you have to wait until the gases return to the synovial fluid. \nMovement of joints, tendons and ligaments: When a joint moves, the tendon’s position changes and moves slightly out of place. You may hear a snapping sound as the tendon returns to its original position. In addition, your ligaments may tighten as you move your joints. This commonly occurs in your knee or ankle, and can make a cracking sound. \nRough surfaces: Arthritic joints make sounds caused by the loss of smooth cartilage and the roughness of the joint surface.<<
448350
My understanding is that it actually hurts it.  If poping it everyday for many years, arthritis could actually form and cause even more pain and make it harder for you to move.  If you are having problems with your back, go see a doctor and see what can be done.
178838
It's like cracking your knuckles. It's cardon dioxide released from your joints. Totally harmless.
14279
I looked up shoulder problems and almost every diagnosis had "clicking" or "popping" as one of the  symptom.  If your shoulder pops or clicks it can mean an injury to the shoulder joint that should be looked at by a doctor.\n\nThe web site noted below has a lot of information and pictures of the shoulder, types of injuries, and symptoms.
671915
Sounds like you are subconsciously making up for the slight immobility in your leg. I can understand why it would cause foot pain, especially in the Achilles tendon, since your inertia as you move would be causing you to be hyperextending your foot. It's probably also connected to the knee pain. You may have developed a habitual limp. Anyone who's ever injured their knee or ankle has experienced the same sort of feeling. I can imagine that this feels completely abnormal though, or else you wouldn't have been describing it here. If you have BlueCross BlueShield, I know that specialists are covered without recommendation under "special office visits". You should have an orthopaedist do an xray to ensure that your cartilage isn't developing elasticity and that it's not flipping around a bone or growth. He should also watch your walk and see what habits you may have developed. Do you have a cane? I've learned that this can cause a weekness in certain muscles, causing others to over-compensate.
585142
According to two different doctors, Chiropractor and a physician, cracking your joints is nothing more than the sound the fluid makes when it passes through, cerebro-spinal fluid I believe but don't quote me on that.  The only harm that comes from 'cracking' your knuckles and other joints is when you must force them to get a 'crack'.  Otherwise it's relatively harmless.
233316
it actually is bad.our bone joints contain a fluid.we hear the pop sound when the air bubbles in that fluid burst.this facilitates the depletion process of the fluid causing brittle bones and other ortho problems.apart from this it is also against etiquette
323531
OK Peeps, there is no adhesive seal between joints, and "cracking your knuckles" is not an unhealthy thing to do. There's no reason to believe it causes arthritis (the inflammation of a joint caused by the degradation of the hyaline cartilage surfaces of the bones) as "cracking" doesn't really cause abnormal joint movement. The pop heard may be caused in two different ways. Pops you can't repeat right away are caused by the release of gas which, while soluble in body fluids, has accumulated in a joint. Second, pops which can be repeated right away are caused by a ligament or tendon moving over a bony protuberance. Neither are bad, especially if done with moderation.
198189
"Cracking Down on Knuckles\n\nYou've all heard the story that cracking your knuckles will cause arthritis. Maybe your mom can't stand that "popping" noise and that's why she tells you knuckle cracking will damage your finger joints. Kidzworld did some digging around to find out what makes that "popping" noise and if it causes arthritis. Here's what we found out. \n\nThe Real Deal on Cracking Your Kuckles\nWhat's really happening when you "crack" your knuckles is that you are either pushing the joint back into or out of its normal position. Joints are the meeting points of two separate bones which are held together by connecting tissues and ligaments. A thick, clear lubricant (made mostly of carbon dioxide and some nitrogen) called synovial fluid is found between the bones. When you stretch or pull your finger to get that desired popping noise, you are causing the bones to pull apart. Pressure is reduced on the synovial fluid and bubbles form that quickly expand and then burst - which is why you get that noise. \n\nDoes Knuckle Cracking Lead to Arthritis?\nNot everybody's joints crack. Some people have a larger separation between the bones and some people can't relax enough to allow the bones to separate. If you can crack and your mom tells you, you're going to get arthritis, she's just yanking your chain. There is no scientific evidence that cracking your knuckles leads to arthritis. However, it can't be good to repeatedly push a joint beyond its normal physical range. Besides that, it's annoying. Cracking your knuckles can cause a decrease in your grip but unless you're signing any multi-million dollar contracts as a pitcher, it's not worth giving up. But it's still annoying."
277288
First, if you are having pain then there is something wrong and you should not just "suck it up".  You need to specify what activities are causing pain and when.  \n\nAsk yourself these special questions:\nIs it sharp pain or dull pain? (chemical vs. mechanical pain)\nIs it intermittent or constant? (activity driven or constant)\nDoes the knee "give way" (esp. with descending stairs)? (possible ligaments instability)\nDoes the knee lock (won't straighten all the way)? (possible loose body in joint or meniscus tear)\nDo you get popping/grinding/"rice crispies" feeling with moving the knee? (possible chondromalacia, osteoarthritis)\n\nThe treatment depends on the problem.
535852
nope it perfectly normal just like cracking the fingers it just compressed hair between bones it nothing unatural and wont harm you some people are more clicky then others some peoples kness crack or their neck so tell your friend not to worry
179584
A single event is not enough to cause damage to the joint, although it is possible that prolonged joint stress due to cracking knuckles may eventually lead to a higher risk of joint damage. The long-term consequences of this practice have not been studied thoroughly, and the scientific evidence is inconclusive. \n\nHowever, the common parental advice "Cracking your knuckles gives you arthritis" may be simply a device to deter children from this practice, which many people find annoying because of the sound it makes. In fact, a study by Castellanos and Axelrod found that arthritis was not a product of knuckle cracking. They evaluated 300 consecutive outpatients at Mount Carmel Mercy Hospital to determine whether habitual knuckle cracking is a risk factor for hand dysfunction. They found no relation with osteoarthritis, but noted that 'knuckle crackers were more likely to have hand swelling and lower grip strength.' (http://elfstrom.com/arthritis/knuckle-cracking.html)\n\nOn a lighter side, there is an online community for "joint crackers" at http://www.jointcrackers.com/ . where you can get community support for your favourite activity ;-).
288800
no it isn't because you use your calf mucles not your knees. might get a little sore the next day though o and about the grindy sound you hear from your knees, i get it too and it means nothing it is just a little friction between your joints
374002
we called them knee bends...hands on hips and lower yourself where your behind touches your heels....then stand back up again, repeat.
419603
I have that habit too, and you don't realize it till you're with a crowd, lost in your thoughts and start cracking away.  The best is when you use your neck muscles to swing and crack your neck and everyone just stares at you.  Or when you open your hand as if to motion "5" then slowly and deliberately crack each finger on the way down to your palm, ending in a fist.\n\nThe best way is to excuse yourself briefly, bathroom, kitchen and so forth.   The way i figure its as if the most active people need to crack their joints.  So be proud!!
469552
Cracking any part of your body, especially the knuckles if done too often can result in arthritis when you get old.  I used to crack things all the time.  How I got over it was just to everytime I would forget and end up cracking my neck or my knuckles I would tell myself in my mind not to do it.  Sometimes I would even reward myself for when I did good for a day then a week and so forth.  The hardest thing is getting out of the habit.  Once you are out, it's easy to never go back to it.
509244
It's an old wives tale. When you crack your finger joints, the popping sound you hear is nitrogen being released. It's not harmful, but you may be annoying the crap out of people around you.