Joints, or articulations, are functional connections between bones that allow for movement. There are three main classifications of joints based on their structure and movement capabilities. Fibrous joints are immovable and connect bones using dense connective tissue. Cartilaginous joints have slight movement and connect bones with cartilage. Synovial joints are fully movable and contain synovial fluid within a joint cavity to facilitate movement. Common synovial joints include ball-and-socket joints, hinge joints, and gliding joints.