Now, as far as I understand, a joint uses cigarette paper to roll the...

现在，据我了解，一个接头使用卷烟纸来卷. . .

Hip and shoulder joints use a ball-and-socket design that allow rotational movement, but the more flexible a joint is, the more unstable and fragile it is — which is one reason why you see so many dislocated shoulders and hip replacements.

髋关节和肩关节采用球窝设计，允许旋转运动，但是关节越灵活，它就越不稳定和脆弱——这也是为什么你会看到这么多脱臼的肩膀和髋关节置换术的原因之一。