Tests on kangaroo shoulder joints reveal how shoulder and knee cartilage behaves differently

If you have survived years of pushing, pulling, lifting, lowering and rotational forces assaulting your shoulders, thank your healthy articular cartilage. It is the smooth, white, lubricating connective tissue covering the ends of bones that meet at a joint. Cartilage promotes low-friction movement and helps bones glide pain-free through a wide range of motion and many functions--when it's healthy.