View full lesson: http://ed.ted.com/lessons/why-do-your-knuckles-pop-eleanor-nelsen Some people love the feeling of cracking their knuckles, while others cringe at the sound. But what causes...
========== What's that sound?Depending on whom you ask,the crackle of popping joints
is either the sound of sweet reliefor the noxious tones
of a stomach-turning habit.Really, though. What's that sound?I mean, why does bending your joints
in a certain way make them pop like that?Scientists have offered
several explanations,including rapidly stretching ligaments,and in severe cases, actual bones
grinding against each other.But the most common explanationfor why your stretched-out joints
sound like bubbles poppingis that, well, there are bubbles in there.The joints in your fingers
are the easiest ones to crack,but many people also crack the joints
between vertebrae in their neck and back,and even their hips, wrists,
shoulders and so on.All these joints are syno...
