What causes the noise we hear when we crack our knuckles or pop other joints?
596348
Escaping 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.
1145818
It's just annoying. I have been popping mine for 30 years. My fingers are slim, straight, have no lumps, bumps or pains.  I recall trying to stop popping them about a year after starting, but found it had become mentally addicting, and physically necessary. Uncracked fingers become cramped and painful. Cracking them loosens them up.\n\nI recall having surgery one time, and did not pop them for a week afterwards. Then one day I realized I hadn't and thought to myself, "do I want to stop, or start again?"  And I happily went and popped every single joint on every finger, and sighed happily in relief.\n\nHearing someone crack their knuckles can be very annoying, irritating, and one must learn to do it when no one else will notice. Then you can enjoy the cracking, and no one else will be bothered.
766937
I think the biggest thing is it bothers other people.  Health wise, I don't know.  I've been cracking my knuckles for as long as I can remember, and I've never had any problems.
88152
Cracking knuckles is the practice of manipulating one's fingers such that the hand (most usually the knuckle joint) produces a sharp sound, likened to cracking (also likened to popping, etc). To produce the sounds, many people will bend their fingers into unusual positions, or manipulate them in ways which are not commonly experienced in everyday use. For example, bending the fingers right back towards the back of the hand, or pulling them away from the hand.\n\nIn many early motion pictures and subsequently parodied in animated cartoons, the gesture of cracking knuckles was associated with a "tough guy" image, especially when accompanied by the implicit or explicit threat of violence.\n\nThe physical mechanism is unknown, but possibilities that have been suggested include:\n\ncavitation within the joint – small cavities of partial vacuum form in the fluid then rapidly collapse, producing a sharp sound (hypothesis in a medical journal) \nthe sudden stretching of ligaments (hypothesis by one reader of that journal) \nrelease of gas from the joints being adjusted (this applies to the popping that can occur in any joint such as during chiropractic manipulation) \nA 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. However, 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 actual fact, study by Castellanos and Axelrod showed 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.'\n\nA chiropractic perspective:\n\n"As a joint is being distracted, the capsule invaginates inward and as the stress on the capsule reaches a certain threshold, it suddenly snaps back from the synovial fluid, increasing the volume of the capsule (and decreasing pressure) and causing the audible sound. The sudden increase in the volume causes the tension to drop, allowing the joint to increase in movement. Eventually, the elastic limit of the capsule is reached and the process stops. The time elapsed during all this is shorter than that required for completion of the stretch reflex, so it can occur without muscular resistance. The sudden jerk on the capsule and the other periarticular tissues is theorized to cause firing of the high-threshold mechanoreceptors."
1037259
its just a build up of fluid in ur finger joints(nothing harmful) that make a sound when u fold ur fingers
304740
because steel expands with heat (and contracts with cold) - so: if too hot, and rails were butted end-to-end, the rails would buckle with obvious BAD consequences! it is the joints that make the clickety-clack sound
994039
It sounds like either little blisters or callouses are forming. Callouses can be front some repetitive action like palying the guitar.
925862
You may have a condition called Tinnitus.  Variously pronounced Tin I tus, or  Tin ee tus.  It can be caused by several things.  Among them are: insult or injury to hearing or certain drugs.  Aspirin will cause it on a temporary basis.  It can get very loud.  William Shatner (Captain Kirk) once head of the Tinnitus Foundation, complains of loud roaring in his ears.  It is annoying but no real threat.  I have it from time to time.  See a doctor for latest treatments.
294611
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.<<
29043
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. However, 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 actual fact, study by Castellanos and Axelrod showed 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'
441700
"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."
308016
It's arthritis. And, no popping your fingers or whatever you pop does not cause arthritis. The only thing it does is releases air that's trapped between your joints.
1167579
Cracking your back by yourself is'nt bad unless your forcing it to pop or crack.    It should be preformed by a professional.  By cracking or popping your joints you are releasing air from the joints and that is good.  A chiropractor has studied the joints and knows which way he or she can manipulate the joints without damaging them.
376899
The "popping" of the knuckles results from forcing joint fluid to very rapidly pass from one side of the joint to the other, where the "sides" are partitioned off by the main bones of the joint.  Let me rephrase that: a joint is an area where two or more separate and distinct\nbones meet.  The joint fluid provides a cushioning between the joints so that they don't grate into each other.  Cracking your knuckles forces the joint fluid from one part of the joint to another, and the popping sound is just the result of the high pressured rushing of fluid.
380833
Absolutely NOT.\n\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?\n\nThere 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.
404241
It's like cracking your knuckles. It's cardon dioxide released from your joints. Totally harmless.
991703
I have the same thing in my elbows when I do push-ups. That did happen to me once in my knees. I had been over-exercising my body, not giving my self enough time to rest. The popping started first, then I got tendinitis in both my knees. \nI would recommend thinking about finding another exercise to stay in shape. The popping sound is the sound of your ligaments and tendons snapping across your bones. To much of that repetitively, and you will cause damage.