After some research done by radiologists, the great debate is approaching its end as doctors say knuckle cracking is not so bad anymore.
This conclusion comes after radiologists found a way to see what happens when we crack our knuckles. They used ultrasound readings and discovered that a crack of knuckles creates a sort of bright flash similar to a firework that explodes in the joint.
What happens when we crack our knuckles
This firework-like flash is coming from a gas bubble that forms in the joint. However, up until now, researchers were not sure if the cracking sound came from this gas bubble forming or from the gas bubble popping.
In order to get the answer to the above dilemma, they combined ultrasound with audio. Using this approach they discovered that the cracking sound comes from the bubble forming and not from the bubbly popping as it was expected.
How they arrived to this conclusion? It seems that the firework-like flash was only visible after hearing the crack. However, the time gap between the two is of only 10 milliseconds.
How was the study conducted
Since this is a quite common habit, 25 to 50 percent of people regularly cracking their knuckles, radiologists conducted a study on a number of 40 people. 10 of them didn’t usually crack their knuckles, while the other 30 had this habit. They were aged 18 to 63.
The participants were asked to stretch their fingers 400 times. These finger stretches were the cause for 62 knuckle cracks. The bubble gas forming and causing the bright flash were seen in almost all cases.
The joints need a fluid that lubricates them. The bubble is made up from dissolved gas suspended in this fluid. Therefore, scientists believe knuckle cracking is associated with the dynamics of changes in pressure in a person’s joints.
Although stretching your fingers creates a negative pressure on your joints that draws out the gas and creates the “cracking fireworks”, it looks like the action doesn’t do you any harm such as loss in strength or swelling. Furthermore, knuckles may experience a significant increase of motion after being cracked, as pressure is released from the joints. This explains why people feel better after cracking their knuckles.
On the other hand, the study doesn’t tell us anything on how this habit may influence us on long-term and whether it could have negative impact on our joints or movements. Researchers claim that for a long-term influence, another kind of study must be conducted in order to get relevant results.
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