He cracked the joints of his fingers.

他把手指关节弄得劈啪作响。

Our fingers bend at the knuckle.

我们手指在指关节处弯曲。

His arm looks like a broken compass;it's not an arm any more, but a knucklebone with a shank attached.

他胳膊活像一指南针，早已不再是一条胳膊，却成加上一条胫骨指关节。

The most common type of joint in the human body is the diarthrodial joint -- knuckles and shoulders are examples -- in which two bones come together in a capsule.

人体中最关节是运动关节，如指关节和肩关节等，关节处一个囊状物把两根骨头结合在一起。