Why Do Knuckles Crack? Engineers Calculate the Answer

Love it or hate it, knuckles crack.For some the noise signals a welcome release, while others cringe at the thought of joints shifting about in their sockets. The sound itself, though, is still a bit of a mystery.
Snap, Crackle, Why?
Researchers have debated the source of the sharp pops for over a century now, and actually thought they had it cracked in the 1970s. The event was simply the sound of bubbles in the sinovial fluid between our joints collapsing, researchers concluded,