Is it okay to crack your knuckles?
The joints and the bones which causes the pop sound is called as synovial joints.These are the most flexible joints in our body. These joints have synovial fluid in between them, which helps in the free movement of the bones.
There are many theories behind the popping of bones, but the most common theory is that in due course of movement of bones there causes a bubble between the joints in the synovial fluid. So when we stretch our bones the synovial fluid it gets expanded and the bubbles inside it get popped and produce a sound.
So does it causes any problems in our joints?
Well, the answer is NO. Popping of bones won't cause any problems in order to prove this a scientist named Donald Unger undertook an experiment of popping only his left hand and the right hand was left unpopped for 50 years. After 50 years an X-ray was taken and it was found that there were no defects in joints. For this noble act, he was awarded a Nobel prize.