Some scientist didn’t believe that the popping noise had anything to do with gas bubbles. To follow up on this hypothesis, some scientist used an MRI to prove the “gas bubble theory” wrong. First, scientist had studied 10 joints by using volunteers’ fingers into a tube. They did this so they could apply traction to the joint. They had specifically used the metacarpophalangeal joints because those were the most common joints that people crack. Then, they took images before and after cracking the knuckles. They shot 3.2 frames per second. According to Medical News Today, “The results showed the rapid creation of a cavity in the joint at the point of joint separation, and this produced the sound.” This result had suggested there may not be a need
