Upper limbs are smaller and shorter. Lower limbs are larger and longer. Upper limbs have skilled motions, like grasping. Lower limbs are weight bearing and have locomotion.Upper and lower extremity fractures involve a break in the continuity of the bones of the upper or lower extremities. The bones may crack slightly or can break into many pieces. Your upper extremity bones include the humerus (upper arm), radius and ulna (forearm), and hand. Your lower extremity bones include the femur (thigh bone), tibia and fibula (shin bone), and foot.