The ends of the bones form the joints. They are meant for smooth movements. So their surfaces are smooth. The joint is enclosed within a capsule that contains synovial fluid. The fluid bathes both the ends and acts like a lubricant There are many theories to explain why cracking of joints produces the sound. One among them is: When the joints are flexed suddenly, the two ends snap against each other producing the characteristic sound. Another theory says that bubbles form within the synovial fluid and when we crack our knuckles, the bubbles burst, causing the sound. The cracking doesn’t cause any damage to the joints.
Knuckle-cracking brings relief to some, while it is a nervous habit for many. It is a common behaviour in people. At some point in time, we have all done it. And we have all come across that person who told us that cracking our joints would give us arthritis. Is it true? There are not many researches that studied the link between knuckle-cracking and arthritis. But there is a popular one by a Canadian doctor, Donald Unger. He won the lg Nobel Prize in 2009 for this study. For more than 60 years, he cracked the knuckles of his left hand at least twice a day, leaving his right knuckles uncracked. He concluded that there was not the slightest sign of arthritis in either hand.
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