Quadriceps Femoris: A muscle group consisting of four muscles (including the vastus lateralis) that is primarily responsible for knee extension.
Patella:A small bone located in front of the knee joint, which articulates with the thigh bone (femur) and is stabilized by muscles including the vastus lateralis.
Knee Extension: The action of straightening or increasing the angle between the femur and tibia, mainly performed by the quadriceps femoris muscle group