3.The tarsal joint of the hind leg of a digitigrade quadruped, such as a horse, corresponding to the human ankle but bending in the opposite direction.

• 四足动物步法至少两只脚总是接触地面，尤指马的步法，四足以四拍的方式踏地，顺序为左后脚，左前脚，右后脚，右前脚