Joints get cushioned and supported by soft tissues that prevent your bones from rubbing against each other. A connective tissue called articular cartilage plays a key role. It helps your joints move smoothly without friction or pain. Some joints have a synovial membrane, a padded pocket of fluid that lubricates the joints. Many joints, such as your knees, get supported by tendons and ligaments. Tendons connect muscles to your bones, while ligaments connect bones to other bones.