What Happens When You Crack Your Knuckles?


Cracking knuckles is a common habit of many people. One study has shown that over 54% of people crack their knuckles for a number of reasons including sound, feeling, nervousness and stress, habit, and lastly, boredom [4]. However, most of us are not aware of what happens if we crack our knuckles. Let’s find out some of the most interesting facts about cracking your knuckles.

What Happens When You Crack Your Knuckles?

When we crack our knuckles, we hear a pop sound. The reason behind this pop is that there is a negative pressure created between the joints when they are pulled apart to form a cavity. The formation of this cavity makes the “pop sound” that we hear. However, a 2018 study showed a different side of the picture. This study concluded that the pop sound was caused due to collapse of the cavity [1].

To prove this concept, researchers reviewed the time it takes to pop your knuckles once again which is around 20 minutes [1]. This is the time required for a new cavity to be formed. Ideally, this is one reason why people cannot crack their knuckles right after they have done it once. This study also gave a more plausible explanation as to why there is a pop sound on the cracking of your knuckles [1].

Researchers at Harvard University have concluded that the pop occurs due to the gas bubbles created in the synovial fluid [2]. This particular fluid helps in the lubrication as well as smooth movements of our joints. When the bones are pulled apart, there is a negative pressure created, and the gas bubbles formed in the synovial fluid “pop” giving the cracking sound one hears.

Illustration of how cracking your knuckles creates a pop

FACT Check – Is Cracking Your Knuckles a Bad Idea?

No, cracking the knuckles does not cause any kind of harm to a person in routine circumstances. One of the most common questions many people have is regarding the negative consequences of cracking your knuckles. Numerous studies have been conducted in this regards which found no significant negative outcome of cracking of knuckles [1].

However, one must keep in mind that if you crack your knuckles with intense pressure, there are chances of harming yourself. This could occur because the joint could get dislocated due to the intense pressure being applied. Studies conducted by Harvard have concluded that there were reports of dislocations and tendon injuries caused due to excessive and forceful cracking of knuckles [3] [5].

Additionally, 1990 research was conducted on 70 people to evaluate the outcomes of knuckle cracking. Researchers found out that chronic-knuckle cracking can lead to loss of handgrip and strength. It could loosen up the joints if done extensively and for a long time [2] [3].

FACT Check – Does Cracking Your Knuckles Cause Hand Osteoarthritis?

This is quite a great misconception among many people and an urban human body myth that cracking your knuckles causes “Hand Osteoarthritis”. In 2018, a study was conducted on 215 people aged 50 – 89 and was conducted to examine any correlation between knuckle cracking and hand osteoarthritis, a condition that causes inflammation and stiffness in hands [3]. The study found that there is no correlation between cracking the knuckles and Hand Osteoarthritis (OA) [3]. Therefore, we can conclude that cracking your knuckles does not cause Hand Osteoarthritis.

However, this does not give a pass to all the knuckle crackers.  Studies have shown that people who excessively crack their knuckles end up with thickened cartilage [6]. The cartilage is a strong and flexible connective tissue that provides extra protection to the joints and bones. This ultimately affects the hand strength and could possibly damage the cartilage and degenerate it over a period of time. The effect is not immediate but could impact your life later on.

Therefore, it can be concluded that cracking knuckles does not cause Hand Osteoarthritis but it does degenerate the cartilage which may lead to swelling in the hands and joint problems later in life [6].

A lady cracking her knuckles

FACT Check – Does Cracking Your Knuckles Create Psychological Issues?

Yes, cracking your knuckles can possibly create psychological issues. One of the most common phenomena related to cracking the knuckles is that it can lead to different types of psychological issues, particularly when it becomes a habit. For instance, repetitive knuckle cracking could make it a permanent habit, and then you might not be able to overcome it.

People might do it in stressful situations, gatherings, meetups, or at any sort of odd time as well because it becomes addictive for a few people to crack their knuckles. As a result, it then affects your personality because people around you can start noticing your extreme habit. The Washington Post suggested that around 20-54% of Americans are excessively engaged in the habit of knuckle cracking which indicates nervous behavior [4].

Cracking your knuckles constantly implies a behavioral disorder in a person [5]. It does not give away a good impression either. Due to psychologically addictive behavior toward cracking knuckles, a person tends to do it more aggressively making high chances for any kind of damage or injury directly to the joints.

FACT Check – Does Cracking Your Knuckles Benefit in Any Way?

Although there isn’t any concrete evidence of this, one study conducted in 2017 found out that there is an improved range of motion in the joints if they are cracked once in a while [4]. However, there isn’t much support for this study as it was conducted on 30 individuals as well [4]. Besides, there are many other activities that these people did apart from cracking their knuckles which could have led to an improvement in joint motion. Therefore, we cannot effectively say that there is any benefit from cracking your knuckles. It is best to avoid this habit because of all the possible “wrongs” mentioned above.

What Happens When You Crack Your Knuckles

Outcomes of Cracking Knuckles – Summarized

Side Effects Benefits
No Short term side effects

Could lead to joint pain in the future

Aggressively cracking knuckles can cause serious injuries

Occasional cracking can lead to a better range of motion in joints.


Cracking your knuckles is a habit for many. However, with the possible outcomes weighing the benefits, it is best to overcome this habit for the long-term betterment of one’s health. Those that do not overcome this habit will tend to increase more and that is the main area of concern. If you also know someone who cracks knuckles excessively, share this useful information with them.


  1. Team, T. H. E. (2019, March 14). Cracking knuckles: Causes, side effects, and tips to stop. Healthline. Retrieved September 8, 2022, from https://www.healthline.com/health/cracking-knuckles
  2. Harvard Health. (2020, July 6). Does cracking knuckles cause arthritis? Harvard Health. Retrieved September 8, 2022, from https://www.health.harvard.edu/pain/does-knuckle-cracking-cause-arthritis
  3. Robert H. Shmerling, M. D. (2020, October 27). Knuckle cracking: Annoying and harmful, or just annoying? Harvard Health. Retrieved September 8, 2022, from https://www.health.harvard.edu/blog/knuckle-cracking-annoying-and-harmful-or-just-annoying-2018051413797
  4. Ellison, K. (2020, October 17). If you crack your knuckles, don’t worry too much about getting arthritis. but the habit isn’t harmless. The Washington Post. Retrieved September 8, 2022, from https://www.washingtonpost.com/health/knuckle-cracking-arthritis-harm-/2020/10/16/5e904d0e-09a6-11eb-a166-dc429b380d10_story.html
  5. Henry County Hospital. (2022, April 25). Why you shouldn’t Crack Your Knuckles. Henry County Hospital. Retrieved September 8, 2022, from https://www.henrycountyhospital.org/news-events/news/2020/december/why-you-shouldnt-crack-your-knuckles
  6. Cleveland Clinic. (2020). Cartilage: What it is, Function & Types. Cleveland Clinic. Retrieved September 8, 2022, from https://my.clevelandclinic.org/health/body/23173-cartilage


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