Movement occurs at diarthrosis (freely moveable) or synovial joints in the body. When looking at joints in the body, movement is characterized according to the plane of motion and axes of rotation in which that joint acts. Some joints are freely movable and are capable of movement in multiple planes and around multiple axes. For example the shoulder and hip are two of the most mobile joints in the body, have a ball and socket structure, and are capable of movement in all three planes. Other joints, such as the knee and elbow are primarily restricted to movement in one plane due to their hinge-like structure.

The shoulder girdle and pelvis can move in multiple planes although these two anatomical structures have no normal joint characteristics. Movement in the shoulder girdle and pelvis are necessary to allow proper movement or stabilization for movement in the highly versatile hip and shoulder.