A joint, such as the elbow, in which a convex part of one bone fits into a concave part of another, allowing motion in only one plane.是什么意思_A joint, such as the elbow, in which a convex part of one bone fits into a concave part of another, allowing motion in only one plane.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句