Final answer:
There are two cruciate pulleys in the knee joint, the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). The ACL resists hyperextension and the PCL prevents anterior sliding of the tibia or posterior sliding of the femur when the knee is bearing weight and flexed.
Step-by-step explanation:
There are two cruciate pulleys located within the knee joint, known as the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). These are intracapsular ligaments that serve distinct functions in maintaining knee stability. The ACL is anchored to the tibia anteriorly at the intercondylar eminence and extends diagonally upwards to attach to the inner aspect of the femoral condyle. It primarily resists hyperextension of the knee. Conversely, the PCL, which is also attached to the tibia at the intercondylar eminence but posteriorly, runs upwards to the femoral condyle and prevents the forward sliding of the tibia or the backward sliding of the femur. The PCL is crucial for stabilizing the knee when it is flexed and weight-bearing, such as when walking downhill.