放于地面 meaning in English

flush with ground

Support the shoulders , chest and ankles with thin pillows in relaxed position
膝关节保持90度(直角) ，双脚连脚?平放于地面或脚踏。
Place the feet on the floor or foot rest with the knee flexed at 90 degree right angle
膝关节保持90度直角，双脚连脚平放于地面或脚踏。
The height of the chair should be appropriate so that the patient s feet can be placed on the floor comfortably , with the hip and knee flexed at 90 xx . xx
椅子高度要适中，使臀部及膝部成度，脚板能平放于地面。