What Causes Our Knuckles to Crack?

Some people love the feeling and the sound of cracking their knuckles, while others wince at it. But what makes that infamous trademark pop? And is it dangerous? Let's discover: Many believe that cracking knuckles are bones realigning themselves, which could not be further from the truth. In fact, knuckles cracking is the audible sound that occurs when the joints in the body are stretched. The cavity in between two knuckles is filled with a fluid known as the synovial fluid. The synovial fluid consists of dissolved gases such as Nitrogen, Oxygen, Carbon Dioxide, etc. If an x-ray were to be taken after effectuating the action of cracking, one would find a gas bubble forming inside the joint. This gas increases the joint volume by 15 to 20% and it consists almost 80% of Carbon Dioxide. The joints cannot be cracked again with a sound until the joints have dissolved back into the synovial fluid. As a result, the normal gap between two cracking pops is between 20 minutes!