Gravity has opposite effects on the arm compared to the leg. It elongates the arm and compresses the leg. 
Gravity tends to elongate the soft tissues of the upper limb. The arm hangs off the axial skeleton and gravity drags it towards the floor. Under the action of gravity the fingers are 'pulled' away from the cervical spine.

In the lower limb gravity tends to bring the foot and the lumbar spine a little closer together. In the upright position gravity exerts a compressive force on the leg.