You rely on your wrists for hundreds of motions, from a quick flick to cut carrots or hands on hips to make a point, to something more exaggerated, even strenuous. Your wrists flex to knead dough, push a lawnmower uphill, type a report. You don't even think about it—until something goes wrong, until the numbness, tingling, and pain are so bad that you wake up in the middle of the night, your hands so weak that uncapping the pill bottle is a struggle.