The first illustration on the left is titled 'A Joint with Osteoarthritis.' The image points out the muscles, bone spurs, synovial membrane, tendons, bone, synovial fluid, cartilage fragments in fluid, and worn-away cartilage. Text: With osteoarthritis, the cartilage becomes worn away. Spurs grow out from the edge of the bone, and synovial fluid increases. Altogether, the joint feels stiff and sore.
The second illustration on the right is titled 'A Healthy Joint.' The image points out the muscles, joint capsule, synovial membrane, tendons, bone, synovial fluid, and cartilage. Text: In a healthy joint, the ends of the bones are encased in the smooth cartilage. Together, they are protected by a joint capsule lined with a synovial membrane that produces synovial fluid. The capsule and fluid protect the cartilage, muscles, and connective tissues.