Final answer:
The knee joint includes three articulations: the femoropatellar joint, the medial tibiofemoral joint, and the lateral tibiofemoral joint. These articulations allow for flexion, extension, and limited rotation of the lower leg, focally managed through both rolling and gliding of the femur over the tibia.
Step-by-step explanation:
The Three Separate Articulations of the Knee Joint
The knee joint, being the largest joint of the body, comprises three separate articulations within a single articular capsule. These are:
The femoropatellar joint, which is located between the patella and the distal end of the femur. This arrangement ensures that the tendon of the quadriceps fumoirs muscle is protected from directly rubbing against the femur during knee movements.
The medial tibiofemoral joint, formed by the articulation between the medial condyle of the femur and the medial condyle of the tibia, allowing the knee to flex and extend.
The lateral tibiofemoral joint, which involves the interaction between the lateral condyle of the femur and the lateral condyle of the tibia.
These joints operate collectively to permit flexion, extension, and minimal rotation of the lower leg, mainly when the knee is flexed. Unique movements such as rolling and gliding of the femur on the tibia are responsible for these actions. The knee's structural design is optimized for weight bearing in its extended position but is susceptible to injury due to hyperextension or twisting.