The Kneecap (Patella) and Knee Joint

The kneecap (patella) is a small triangular bone. It is just one of the many parts that make up the knee joint. Some of the other parts are muscles, ligaments, and leg bones. The kneecap provides leverage for your muscles as they bend and straighten the leg. It also protects the knee joint.

The Kneecap Up Close

Take a closer look at this small bone to see how it works.

From the front, you can see the kneecap’s slightly rounded, shield-like shape.

From the back, you can see cartilage. This is tough tissue that covers the bone. It helps the kneecap slide easily against the thighbone.

From the top, you can see that the kneecap sits in a groove or “track” in the thighbone.

A closer view of the kneecap shows the difference between the smooth cartilage and the rougher bone beneath.