Which structure cushions joints and reduces friction?

Which structure cushions joints and reduces friction?

• A. Bones
• B. Muscles
• C. Ligaments
• D. Cartilage

Answer: (D)

Cartilage provides a smooth, resilient cushion between the ends of bones, reducing friction as joints move. The articular cartilage that covers joint surfaces is designed to be very slippery and capable of absorbing some load, so it helps bones glide smoothly rather than grate against each other. This combination of a low-friction surface and shock absorption keeps joints moving comfortably. In contrast, bones give structure, muscles produce movement, and ligaments stabilize joints; none of these primarily cushion or reduce friction between articulating surfaces. Some joints also use fibrocartilage, like the knee’s menisci, to further cushion and distribute load, but the general structure dedicated to reducing friction is cartilage.