What is the name of the triangular shaped bone that lies over the anterior portion of the knee joint?

The triangular shaped bone that sits over the anterior portion of the knee joint is known as the patella, commonly referred to as the kneecap. Its primary role is to protect the knee joint and to aid in the efficiency of the quadriceps muscle in extending the leg. The patella acts as a fulcrum, enhancing the leverage that the quadriceps has when it contracts. This structure contributes to the stability of the knee joint during movement and plays a crucial role in activities such as walking, running, and jumping.

The other bones listed, while important in the anatomy of the leg and knee, serve different functions. The femur is the thigh bone and longest bone in the body, while the tibia is one of the shin bones, and the fibula runs alongside the tibia. None of these bones are positioned directly over the knee joint in the way that the patella is.