Knuckles and Joints: Does Cracking Your Knuckles Cause Joint disease?


MNT Knowledge Center

Joints can make a variety of sounds – playing a percussive symphony of popping, cracking, creaking, grinding and snapping noises.

The joints that “crack” are frequently the knuckles, knees, ankles, neck and back. There are many explanations why these joints “seem off,” but, can your knuckle-cracking habit cause or exacerbate joint disease? Is cracking your knuckles and joints yet another harmless habit?1,2,7,24

For many, joint cracking is really a nervous habit for other people the feeling brings relief. Based on which research you read, between 25% and 54% of individuals crack their knuckles, with men more prone to achieve this than women.14-16 Let’s take particular notice at joints, why they crack and when cracking them causes any health problems.

Contents of this article:

  1. Joints, knuckles and their uses
  2. Why do people pop their joints?
  3. Does cracking your joints / knuckles cause arthritis?
  4. What causes cracking joints?
  5. Do the cracking sounds need to be treated?
  6. Should you be worried about the cracking and popping of a joint?
  7. Taking care of your joints

Additionally, you will see introductions in the finish of some sections to the recent developments which have been included in MNT’s news tales. Also consider links to details about related conditions.

Fast details on joint cracking

Here are a few tips about joint cracking. More detail and supporting information is incorporated in the primary article.

  • Joint cracking brings relief to some people, for others it is a habitual act.
  • The interphalangeal and the metacarpophalangeal joints in the fingers are the easiest joints to crack.
  • The “popping” sound is thought to be gas bubbles imploding and collapsing in the synovial fluid that surrounds the joints.
  • Usually it takes 25-30 minutes to be able to crack knuckles again after cracking.
  • X-rays show that gas bubbles remain present in the synovial fluid for up to 20 minutes after cracking.
  • Cracking sounds can also be triggered by tendons snapping over a joint.
  • Movement from a joint with worn cartilage can make a grinding sound – called crepitus.
  • Joint cracking has not been shown to cause arthritis.
  • People who crack their joints show a higher rate of inflammation of the hands and weaker grip.

Joints, knuckles and their uses

The joints are the parts of the body where the ends of two bones come together, with joints coming in several shapes, sizes and types:1,3

man cracking knuckles
Between 25-54% of people crack their knuckles, with men more likely to do so than women.

Types of joints

  • Pivot joints: allow rotary movement. For example, allowing side to side motion of the head, and the twisting movement of the forearm bones against the upper arm
  • Hinge joints: a class of synovial joint that includes the ankle, elbow and knee joints. Hinge joints are formed between two or more bones where the bones can only move along one axis to flex or extend
  • Ball-and-socket joints: a joint in which the rounded surface of a bone moves within a depression on another bone. Such joints allow greater freedom of movement than any other type of joint and are most highly developed in the large shoulder and hip joints
  • Gliding joints: occur between the surfaces of two flat bones held together by ligaments. For example, some of the bones in the wrists and ankles move by gliding against each other
  • Saddle joints: allow for two different types of movement. For example, a saddle joint allows your thumb to move toward and away from your forefinger as well as crossing over the palm of your hand toward your little finger
  • Condyloid joints: similar to ball-and-socket joints, minus the socket. Instead, the “ball” simply rests against the end of the bone.

The ends of bones at these joints are covered with articular cartilage and surrounded by a “joint capsule” containing synovial fluid. It is this protective fluid that serves as a lubricant for the joint, cushioning the cartilage and tissues. Synovial fluid is also a source of nutrients for the cells that maintain the joint cartilage. Synovial fluid contains dissolved gasses such as oxygen, nitrogen and carbon dioxide.1,3,9

Why do people pop their joints?

Many people find joint cracking satisfying, encountering an actual release, sense of looseness and elevated mobility for a while after cracking the joint. Others crack their joints from habit, in exactly the same as individuals who twirl their head of hair or jiggle their feet up and lower.

Regardless of whether you have cracked your knuckles for a long time, get it done like a nervous habit, or hear the periodic pop or crack when working throughout the house – you’re not alone in wondering exactly what the cracking is and just what it will for your joints.9

Does cracking your joints / knuckles cause arthritis?

People tend to crack their joints in one of three ways: bending them backward or forward; turning them sideways; or pulling on the bones around the joint. While any joint can be popped, it is the knuckles of the fingers that are most commonly popped.9

hand with arthritis
Cracking your knuckles does not cause arthritis.

Many people are repulsed by knuckle cracking, and fogeys frequently attempt to curtail the habit of smoking within their children, believing that cracking the knuckles can result in joint disease later in existence.7 Is that this true, or perhaps is cracking the knuckles and popping the joints only a harmless habit that annoys many people?

Cracking your knuckles may aggravate the folks surrounding you, but it’ll most likely not lift up your risk for joint disease. A minimum of, that’s the conclusion of countless studies that in comparison rates of hands joint disease among habitual knuckle crackers and individuals who don’t crack their knuckles.2

One study discovered that there wasn’t any rise in hands joint disease among knuckle crackers. However, knuckle cracking was associated with hands swelling minimizing grip strength.3,4

Another study established that while knuckle cracking wasn’t connected with joint disease, it had been connected with dislocation of tendons and harm to ligaments that surround the joints. So, while cracking your knuckles isn’t considered to cause joint disease, it can lead to soft tissue injuries.3

Dr. Donald Unger

In 1998, Dr. Jesse Unger printed instructions titled “Does knuckle cracking result in joint disease from the fingers?” towards the editors of Joint disease and Rheumatism, the earth’s premier rheumatology journal.7

Dr. Unger reported he have been cracking the knuckles of his left hands a minimum of two times daily on the 50-year period, as the right hands never was cracked and utilized as a control.7

The knuckles around the left were cracked a minimum of 36,500 occasions, while individuals around the right cracked rarely and automatically.8

Unger authored, “Throughout the author’s childhood, various famous government bodies (his mother, several aunties and the mother-in-law) informed him that cracking his knuckles would result in joint disease from the fingers.” He continued to utilize a half-century “to check the precision of the hypothesis.”

Finally, after 50 years, Unger examined his data set: “There wasn’t any joint disease either in hands, with no apparent variations backward and forward hands.” He came to the conclusion, “There’s no apparent relationship between knuckle cracking and also the subsequent growth and development of joint disease from the fingers.”

Fittingly, Dr. Unger was granted this year’s Ig Nobel Prize for Medicine. These honours are presented yearly around the eve from the real Nobel Awards through the organization Research for “accomplishments that first get people to laugh, and then suggest them think.”7

Throughout the ceremony for accepting his award he discrete a cry, “Mother, you had been wrong!”10

Swezey and Swezey

Answering the Unger paper, Dr. Robert Swezey, authored towards the journal to are convinced that his 1975 study also found no situation for that theory that knuckle cracking causes joint disease. The 28 participants from the study were citizens inside a Jewish elderly care in La these were requested whether or not they had ever cracked their knuckles habitually. Individuals who’d cracked their knuckles were less inclined to have osteo arthritis within their hands afterwards.

Swezey further consulted Rand Corporation statistician John Adams, who noted, “It seems the [Unger] study wasn’t distracted. Blinding would simply be possible when the investigator did not know left from right. This isn’t likely since reports say that just 31% of primary care doctors have no idea left from right.”7,8

Uniformed Services University of the Health Sciences

In research carried out lately, researchers within the Uniformed Services College in the Health Sciences made a decision to resolve the problem of knuckle cracking link with osteo-arthritis permanently.9

The researchers incorporated 214 people the study, 20% who sprang their knuckles regularly. Of people knuckle crackers, 18.1% in the had osteo-arthritis inside their hands, compared to 21.5% in the study participants who did not crack their knuckles.

The study shown that the probability of getting osteo-arthritis are virtually the identical whether or not you crack your joints or else. However, osteo-arthritis is not the only real concern for individuals who crack their joints.

Inflammation and weak grip

While joint popping might not cause joint disease, it’s not completely risk-free. In a minumum of one study, chronic joint popping was proven to result in inflammation and destabilized grip in the possession of.10

A sizable study in 1990, carried out through the Department of Internal Medicine, Mount Carmel Whim Hospital, in Detroit, centered on 300 participants older than 45, 74 who cracked their knuckles, while 226 didn’t.10

Both groups demonstrated similar rates of joint disease within their hands. However, the 74 who cracked their joints demonstrated a greater rate of inflammation from the hands along with a less strong grip. So, while joint cracking might not cause joint disease, it may have a negative effect on the general health insurance and strength of hands.10

The authors say what this means is knuckle cracking ought to be frustrated, however the study does not address the issue whether those who cracked their knuckles might have felt more discomfort within their hands to begin with.

Many highly respected medical facilities and sources, including Harvard and the Johns Hopkins Arthritis Center, have stated that joint cracking does not cause arthritis.9 Habitual joint cracking does not correlate with arthritic changes but does correlate with loss of grip strength and soft-tissue swelling.22

Taking an engineering approach, cracking the knuckles frequently over many decades could theoretically damage the cartilage since the joint. Evaluations have occurred using the mechanical deterioration built up with time by ship’s propellers, however the evidence the same is going on in people’s hands is thin.4,17

Just how did the thought of rapport between knuckle cracking and joint disease emerge? It is a fact that individuals who curently have joint disease sometimes find their joints crack since the cartilage of the top of joints continues to be broken. However, it’s unusual with this is the first symptom, and it is more probably to originate from damage, as opposed to a cause.

Established risks for joint disease include age, a household good reputation for the problem, previous accidents concerning the hands(s), along with a duration of dealing with both your hands (like a career in heavy work).19

Around the positive side, there’s proof of elevated mobility in joints immediately after popping. When joints are altered, this encourages the Golgi tendon organs (some nerve being active in the feeling of motion), which in turn relaxes the muscles all around the joint. This really is one of the reasons why people report feeling “loose” and invigorated after departing the chiropractor’s office, where cavitation is caused included in the treatment. The rear, knees, elbows and all sorts of other movable joints are susceptible to exactly the same kind manipulation as knuckles.23

On the next page we look at what causes cracking joints, whether you should be worried about the cracking and popping of a joint and how to take care of your joints.


MNT Knowledge Center

(Continued from page 1…)

What causes cracking joints?

Joint cracking is a poorly understood phenomenon.13 The exact reason joints pop and snap is not known, although there are a few theories, which are discussed below.

The easiest joints to pop are the ones in your fingers – the interphalangeal and the metacarpophalangeal joints, which are hinged diarthrodial joints.

Knuckle cracking

Synovial fluid bubbles and cavitation

When a finger or joint is extended, the pressure inside the finger is lowered and the gases that are present, such as carbon dioxide, are released in the form of a bubble. This action creates a vacuum that the gases then fill.

x-ray of normal hands
People crack their joints either by bending them backward or forward, turning them sideways, or pulling on the bones around the joint.

As the pressure of the synovial fluid drops, gasses dissolved in the fluid become less soluble, forming bubbles. When joints are extended through pulling, there is a sudden and dramatic increase in surrounding pressure that causes a corresponding sudden partial or total collapse of these gas bubbles.23,27

This rapid implosion, collapse or bursting of the gas bubbles creates an audible popping sound. The bubbles pop when the bones are pulled apart, either by stretching the fingers or bending them backward, creating negative pressure.1,2,7,10

It takes about 25-30 minutes for the released gases to dissolve back into the synovial joint fluid. During this period, the knuckles will not crack. This released gas increases the joint volume by 15-20%, with most of the gas (about 80%) consisting of carbon dioxide.10,22 Once the gas has dissolved once more, cavitation can reoccur and the knuckles can be popped again.23

According to X-rays taken shortly after knuckle popping, there are many smaller gas bubbles that continue to be present for up to 20 minutes. Once a joint undergoes cavitation, the force-displacement curve changes and the range of motion of the joint increases.

When small forces are applied to the joint, one factor that limits the motion is the volume of the joint. That volume is set by the amount of synovial fluid contained in the joint. The synovial fluid cannot expand unless the pressure inside the capsule drops to a point at which the gases can dissolve out of the solution; when the gases dissolve out of solution, they increase the volume and mobility of the joint.21

Researchers have estimated the energy levels of the sound by using accelerometers to measure the vibrations caused during joint popping. The amounts of energy involved are miniscule, on the order of 0.1 millijoule per cubic millimeter. Studies have also shown that there are two sound peaks during knuckle cracking, but the causes of these peaks remain unknown. It is likely that the first sound is related to the gas dissolving out of solution, while the second sound is caused by the capsule reaching its length limit.21

Nitrogen bubbles in the fluid inside the joint are rapidly brought into or out of solution when the joint is manipulated, such as cracking the knuckles of the hand. The resulting noise may sound like folding stiff paper, especially upon movement of a joint such as the knee. These noises typically increase in frequency after surgery on a joint, although the reason for that remains unclear.6


The bubble collapse theory of joint popping has recently been debunked by Canadian researchers on the basis of visual evidence of what actually happens in the joint when it cracks. By collecting real-time footage using magnetic resonance imaging (MRI), the researchers in Alberta, Canada, concluded that joint cracking is related to cavity formation rather than the collapse of gas bubbles.29

The scientists studied 10 metacarpophalangeal joints by inserting volunteers’ fingers into a flexible tube that could be used to apply traction to the joint. They took images using MRI before and after traction and took 3.2 frames per second when traction was applied to the point of cracking.

The results showed the rapid creation of a cavity in the joint at the point of joint separation resulting in the production of sound. The cavity remained visible after the noise.

This research suggests that for joints to be cracked, there need not be existing gas bubbles. Instead, the cracking of the joint itself may be sufficient to cause rapid cavitation and the popping sound.


Crepitus is a type of joint clicking that resembles a grinding sound and which results from friction between cartilage and bone, or in fractured bone.

Tendons snapping over joints

Joint cracking is often confused with the snapping sound made by stiff tendons or other bands of soft tissue sliding between muscles or over bony outcrops.7

According to Johns Hopkins Department of Orthopedic Surgery, this sound originates from tendons and ligaments. Tendons keep muscles attached to bones and are like rubber bands stretched over the joints. Similarly, ligaments extend to connect bones to other bones. Doctors believe that tendons can make a popping noise when they quickly snap over a joint. Ligaments may make popping noises when they get tight while the joint is moving.1

When a joint moves, this forces a change in the tendon’s position relative to the joint. It is not uncommon for a tendon to shift to a slightly different position, followed by a sudden snap as the tendon returns to its original location with respect to the joint. These noises are often heard in the knee and ankle joints when standing up from a seated position or when walking up or down the stairs.21

Sternum and rib clicking

Some of the causes of the clicking of the sternum or rib may include:

  • Trauma: injury to the chest area, such as from assault, falls or car accident injuries
  • Physical strain: this may be seen in excessive weight lifting or other activities that put pressure on the chest wall, its muscles and bones. A person who supports their body weight on one hand or elbow over long periods may transfer the weight across the costal cartilage and strain the joint possibly leading to inflammation or sublaxation
  • Costochondritis: this is inflammation of the costal cartilage and usually affects the fourth to sixth ribs. It may be caused by infections, postoperatively (like in cardiothoracic ‘open heart’ surgery) or after repeated minor trauma or physical strain. Pain and tenderness are usually present although swelling is not typically evident
  • Tietze’s syndrome: similar to costochondritis, except the second and third ribs are usually affected, and it more commonly occurs in young girls. Apart from pain, there is also detectable swelling. It is usually caused by repeated minor trauma or physical strain, including persistent coughing or repeated vomiting
  • Muscle spasm: this can cause sublaxation of the joint, because tight muscles restrict functional flexibility. This is usually accompanied by chest pain
  • Osteoarthritis or rheumatoid arthritis: these types of arthritis do not commonly affect these joints or cause clicking, but joint degeneration linked to chronic arthritis could cause a grating sound
  • Calcification of the costal cartilage.

Shoulder joint pop, crack or click

If there is no pain experienced with cracks or clicks, the soft tissue in a joint is identified as the cause. Noises that are associated with pain may indicate damage to the surfaces of the joint. Such cracks and clicks may be due to tears in labrum, a ring of cartilage that acts like a rubber seal around the shoulder joint. The labrum may snap over the other structures of the shoulder joint as the arm moves. When there is a labral tear at the top of the shoulder, it is referred to as a slap lesion. Sometimes the clicking may be due to the shoulder slipping in and out of joint. This is known as shoulder instability.12

Do the cracking sounds need to be treated?

Whatever the cause of joint cracking and popping, the sounds themselves do not require specific treatment. There are no known long-term sequelae (chronic health issue) associated with these noises, and there is no basis for the warning to “not crack your knuckles because it can lead to arthritis.” There are also no supplements or exercises proven to prevent these noises.6

Should you be worried about the cracking and popping of a joint?

For the most part, the cracking and popping of joints is normal and nothing to be concerned about.6

The time to worry about cracking or popping a joint is when the sounds are accompanied by pain. Joint swelling is also abnormal and should be assessed by a health professional. If the joint gets locked or stuck when it pops or cracks this may also indicate a joint problem and should be evaluated. If there is decreased motion of the joint, swelling or a loss of joint function, it is important to seek medical advice and treatment.6

Taking care of your joints

The most important thing to know about joint health is that prevention is better than treatment. Achieving and maintaining an appropriate body weight helps to lessen pressure on the joints and is best achieved by engaging in regular, low-impact exercise so as to minimize the risk of injury, while strengthening muscles to better support the joints and act as a shock absorber.1

So, if you like cracking your knuckles then by all means carry on. Just bear in the mind the conclusions of the doctors who carried out the research in the LA nursing home. They said: “The chief morbid consequence of knuckle cracking would appear to be its annoying effect on the observer.”15


  1. the game have video memory leaks issues , you have been warned

  2. In my opinion, no developer has a duty or respo1ibility to portray elements of real life in a way that is deemed acceptable and positive by an arbitrary set of guidelines by advicate groups.nThis criticism of the game just seems wrongheaded and entitled to me. And it doesn’t even effect the gameplay itself

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