Posterior dislocation of the femur on the tibia is prevented by

CRUCIATE LIGAMENTS: Very thick and strong fibrous bands.Direct bonds of union between tibia and fibula.Maintain anteroposterior stability of knee joint. Anterior cruciate ligament:- Begins from anterior pa of intercondylar area of tibia, runs upward, backward and laterally and is attached to the posterior pa of medial surface of lateral condyle of femur. Taut during extension of knee. The anterior cruciate ligament is more commonly damaged than the posterior.It may be injured in violent hyperextension of knee or anterior dislocation of tibia. Posterior cruciate ligament:- Begins from posterior pa of intercondylar area of tibia, runs upwards, forwards and medially and is attached to lateral surface of medial condyle of femur. Taut during flexion of knee. The posterior cruciate ligament is injured in posterior dislocation of tibia. It prevents posterior dislocation of femur on tibia. Both these are supplied by middle genicular nerves and vessels. {Reference: BDC 9 E}