There are three primary classifications of joints, only two of which are movable: fibrous (immovable), cartilagenous (slightly movable) and synovial (freely movable). However, there are several subcategories of movable joints within the synovial category, such as ball-and-socket, hinge, gliding, pivot and compound joints.
Synovial joints, like the hip and shoulder joints, are the most common joint types in the skeletal system. They are the only joints that have fluid-filled cavities and allow for angular and circular movement. Cartilagenous joints are partially movable and consist of fibrocartilaginous fusion between two bones. The pubic bone, jawbone, rib cage and spinal column are cartilagenous. The immovable fibrous joints in the human body are the sutures of the skull.
Ligaments hold fibrous joints together, whereas cartilage holds cartilagenous joints together. Synovial joints, on the other hand, are surrounded by synovial capsules.