There are two kinds of people when it comes to cracking your fingers – those who love to do it and those who can’t stand to hear it. No doubt you grew up hearing that cracking your knuckles will lead to arthritis in your hands, or make your knuckles thick and ugly. In a somewhat surprising twist, science was long unable to answer the question of whether cracking your fingers is bad for you. It was only in recent years that the cracking or popping sound was explained along with what was happening inside the joint.
What happens inside
What is really going on inside your joint? Cracking a joint is also called articular release. You stretch the joint past the degree of usual rotation (or flex it backward, depending on the joint) and there is a feeling of tension building then a pop! The tension is released, the joint is relaxed and satisfied. This process is not intuitive. What is inside a joint that can make a loud noise like that? What are the long-term effects of cracking the joint, if any?
Cracking the Code
Back in 1939, there was a theory that the sound of popping was made by the capsule around the joint snapping back to adhere around the newly adjusted joint. In 1947, this theory was replaced by one that stated that the pop was the result of a vibration produced when the joint rotated past its normal angle of functioning.
It was not until 1971 that researchers hypothesized what turned out to be the correct explanation. Synovial fluid is the lubricant, located around and between the bones of the joint. Bubbles of gas (oxygen, nitrogen and carbon dioxide) form in the synovial fluid. When the joint cracks, the bubbles of gas coalesce in the joint and are suddenly released by the movement that produces the crack. Synovial fluid rushes back in where the gas had been. This sudden release of the gas makes the relatively enormous popping sound.
This theory was finally supported by medical evidence when a person cracked his knuckles in an MRI. The gas can be seen and is seen to dissipate. Subsequent research showed within the extreme detail of an MRI that the bubbles are actually still present after the crack. Still, further study involving a mathematical model showed that most bubbles were dispersed and they were sufficient to make the familiar sound.
Why is it so loud?
Acoustics is a measured science that is not open to much interpretation. The size of the gas bubbles released when the finger joint is cracked within the structure of the finger gives rise to what sounds like a disproportionately loud sound. But it’s actually just physics!
So is it safe?
There is no evidence that cracking your fingers is harmful. People who frequently crack their knuckles do not get arthritis more than people who do not crack their knuckles unless there happens to be another condition present like tendonitis or arthritis. If it hurts when you do that, don’t do that.
Pain in the finger joints when you crack your knuckles or any pain in the hands, wrists, or shoulders needs to be addressed by a specialist who diagnoses and treats conditions affecting these areas. Don’t risk the function of your hands by trusting your treatment to just anyone. The board-certified hand surgeons and specialists at Greater Chesapeake Hand to Shoulder practice at locations throughout Maryland. Our main office number is (410) 296-6232. Call for an appointment today or request an appointment online at one of our locations in the Greater Chesapeake area.
