The human skeleton..?

It's fun, isn't it! It can be hard but stick with it! Hinge (think of a door, with movement backward and forward): between the humerus (upper arm bone) and the ulna and radius (lower arm bones) or the femur (thigh bone) articulated to the tibia and fibula (lower leg bones); Pivot (allows for rotation): the atlas and axis (top vertebrae right underneath the cranium) to the vertebral column (the spine) and allows you head to rotate; and finally Ball and Socket (rotation is possible in many directions): where the head of the femur articulates to the os coxae (hip bone) and also where the head of the humerus articulates to the scapula (shoulder blade).