时差N小时 如何判断自己是不是双关节?(上)（在线收听）

Can you bend your thumb backwards until it touches your wrist?

你是否能向后弯曲大拇指，让它触碰到手腕部位吗？

If you join your hands behind your back, can you lift them over your head without letting go?

如果将双手紧握在背后，你能否将其举过头顶而不松手？

If you can, you might be what some people call double-jointed.

如果你可以做到，那么你可能拥有“双关节”。

But, A Moment of Science wonders, how could anyone have double joints?

不过，《科学一刻》想知道，人怎么可能拥有双关节呢？

Double-jointed people don't really have two joints.

所谓“双关节”并不是指真的拥有两个关节。

Any joint, such as the thumb joint or the shoulder, can be called double-jointed if the tendons and ligaments surrounding the joint allow a wider range of motion than is usual.

任何关节，如肩关节或拇指关节，若其四周的韧带和肌腱的可活动范围超出普通值，就可以被称为“双关节”。

Joints are created whenever two adjacent bones meet.

关节是两骨相接而形成的。

They have fibrous bands of connective tissue called ligaments that stabilize the joint.

他们有“纤维状”结缔组织——韧带，而韧带能够稳固关节。