Have you ever wondered what happens when you crack your knuckles, back, neck or other joints? Are you curious about what causes the popping sound that's associated with cracking a joint?
In addition to curiosity about the physical process, many worry that joint cracking is harmful and it's often rumored to cause arthritis.
What Causes the Popping Sound When You Crack Knuckles or Other Joints?
When you crack your knuckles or another joint, it results in a popping sound. This sound is actually the result of a popping gas bubble. To understand how and why this occurs, it's important to understand the joint structure and the joint cracking process.
Joints are supported by ligaments and other connective tissues; the ligaments hold the joint in the proper position. There is also a sac of fluid surrounding the joint. This fluid is called synovial fluid and like a carbonated beverage, the liquid contains dissolved gases.
When you crack a joint, the fluid sac is stretched. This results in a momentary increase in the sac's volume. Like a bottle of soda that has just been opened, the dissolved gases form a bubble. Within an instant, the bubble pops and it's this that causes the popping sound that's associated with joint cracking.
It takes approximately one-half hour for the gases to re-accumulate in the joint fluid. This is why you cannot crack joints repeatedly.
Does Joint Cracking Cause Injury?
According to an article titled "The Audible Release Associated with Joint Manipulation," Dr. Raymond Brodeur examined hundreds of patients and he concluded that joint cracking does not cause arthritis, nor does it result in injury.
The act of cracking joints does stretch the ligaments and connective tissues that hold the joint together, and according to Dr. Brodeur, some individuals did experience a weaker-than-normal grip after a knuckle cracking session. It's believed that this is a result of ligament stretching and the slight inflammation that can result from cracking joints.
Notably, according to Dr. Brodeur's research, many individuals actually experience positive effects from cracking joints, such as a sensation of improved mobility.
If you experience pain when joints crack, it's important to discuss these symptoms with your physician as this could be an indication of an underlying problem. Frequent, unintentional joint cracking can also be a sign of a connective tissue disorder such as Ehlers–Danlos syndrome; the condition is also associated with extreme joint mobility, unusually "stretchy" skin and frequent joint dislocation.
Many individuals also experience an uncontrollable jaw popping sensation, but the cause is a bit different. To learn more, read 'Why is My Jaw Clicking and Popping?"
Disclaimer: The information contained in this article is for educational purposes only; it should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his/her health should contact a licensed medical professional.
Sources
- 'The Audible Release Associated with Joint Manipulation,' by Raymond Brodeur, D.C., Ph.D. Published in The Journal of Manipulative and Physiological Therapeutics, March/April, 1995.
- Class Notes from "Introduction to Anatomy" at Simmons College. Fall 2005.
Mia Carter - Mia Carter - Journalist, Producer/Editor & Web Writer. Carter's work has appeared on CBS and CNN.com.
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