roller joint

• 球节

roller joint的用法和样例：

例句

1. The toe of the raised hind leg should reach just above the fetlock joint of the other hind leg.
   后蹄尖抬起的高度应刚好达到另一侧后肢球节的上方。
2. Viewed from the side, pasterns are slightly slanted, with the pastern joint strong, but flexible.
   从侧面看，球节略微倾斜，坚固，但是是灵活的。