Which three bones make up the knee joint?

The knee joint is primarily composed of three bones: the femur, tibia, and patella. The femur, or thigh bone, connects to the tibia, which is the larger bone of the lower leg, forming the main hinge joint responsible for the bending and straightening of the knee. The patella, also known as the kneecap, sits in front of the knee joint, providing protection and improving the mechanical efficiency of the quadriceps muscle by increasing the leverage of the tendon.

The interaction between these three bones facilitates not only stability and mobility but also weight-bearing functions. Understanding the anatomy of the knee joint is crucial for recognizing its mechanics and potential injury outcomes, particularly in activities involving running, jumping, or squatting, which put stress on the joint.

Other options include bones that do not directly form the knee joint. For instance, the fibula is a smaller bone located adjacent to the tibia and does not contribute to the knee joint's articulation, while the humerus is an upper arm bone and has no connection to the knee structure.