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.
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 synovial fluid between our joints collapsing, researchers concluded, the result of something called cavitation. The phenomenon describes the formation of bubbles in a fluid when the pressure drops, often as a result of movement, and it can be powerful enough to damage ship propellers and pump components.
The same thing happens in our joints when we stretch them out a bit — the sudden expansion lowers the pressure and bubbles form, only to disappear when the pressure ...
