What anatomical structure allows a joint to move freely by providing cushioning at friction points?

The anatomical structure that allows a joint to move freely by providing cushioning at friction points is the bursa. Bursae are small, fluid-filled sacs located near joints that reduce friction between moving parts, such as tendons, ligaments, and bones. They act as cushions and enable smooth and pain-free movement, especially in areas where soft tissues glide over bony prominences.

While cartilage, ligaments, and tendons play important roles in joint function, they serve different purposes. Cartilage provides a smooth, slippery surface for bones to articulate with each other and absorbs shock, while ligaments connect bones to other bones, providing stability to the joint. Tendons attach muscles to bones, facilitating movement. Bursae specifically target the reduction of friction, which is essential for ensuring a full range of motion and protecting the surrounding tissues in a joint.