What's the scientific word for your kneecap?
And the answer: patella.
In short, your patella is your kneecap. It's a small bone located in front of your knee joint, where the thighbone and shinbone meet. Your patella protects your knee, and connects the muscles in the front of your thigh to your shin.
This small but fascinating bone is essential to everyday function. While some animals are born without it (sorry, ostriches), it helps humans protect the vital muscles and ligaments that meet in your knee. The patella also increases the leverage of the knee's straightening muscles, so not as much force is needed to straighten the knee.
While the patella is a reasonably small bone in your body, it is the largest sesamoid bone we have, which means it is embedded within a tendon. In the patella, the quadriceps and patellar tendons meet. There, the rounded triangular bone protects the knee joint and acts like a pulley, allowing the tendon to transmit more force with smoother motion. As such, the patella is able to bear quite a lot of weight — up to 8 times as much, in fact! When climbing stairs, the patella bears up to 3 times your body weight, and when doing a deep squat it can take as much as 8 times your weight. Pretty impressive for such a small bone!
Interestingly, though, patellas don't start out quite as strong. They actually begin as cartilage in babies, unconnected from the rest of the skeleton. The patella slowly begins to turn into bone between the ages of 2-6 years old.
Learn more about the patella here.