What are the primary movements involved in the range of motion of the knee?

The primary movements involved in the range of motion of the knee are flexion and extension. The knee joint primarily serves as a hinge joint, allowing it to bend (flex) and straighten (extend). During flexion, the angle between the thigh and the lower leg decreases, which occurs when the heel moves toward the buttocks. In contrast, extension increases the angle between the thigh and the lower leg, straightening the knee back to its normal position.

While there are some rotational movements that can occur at the knee joint, especially when the knee is flexed, flexion and extension remain the fundamental movements that define the knee's range of motion. This functioning is crucial for various activities such as walking, running, and jumping, as the knee must effectively bend to absorb impact and extend for propulsion.

Other movements listed, like abduction and circumduction, are not primary movements of the knee, which clarifies why they do not capture the essential mechanics of this joint. The complexity of the knee does permit slight rotation and other movements under certain conditions, but these are secondary and not the primary focus when discussing the knee's function.