Final answer:
Synovial joints are stabilized by ligaments, which come in extrinsic, intrinsic, and intracapsular forms, as well as supported by articular cartilage, synovial fluid, and tendons from surrounding muscles.
Step-by-step explanation:
At synovial joints, the joint capsule is reinforced by ligaments that help stabilize the joint and bind together the bone ends. These ligaments include extrinsic ligaments, which are located outside of the articular capsule, intrinsic ligaments that are fused to the wall of the capsule, and intracapsular ligaments found inside the capsule. The stability of synovial joints, like knees, elbows, and shoulders, is also enhanced by the presence of articular cartilage and synovial fluid, which allow for smooth movements and reduce friction between bones. Muscles and their tendons acting across a joint also contribute to joint support by increasing contractile strength when needed.