The ACL prevents the femur from moving forwards during weight bearing.
These, along with the muscles acting on the knee, provide the joint’s stability. The major ligaments of the knee are the Anterior Cruciate (ACL), the Posterior Cruciate (PCL), and the Medial (MCL) and Lateral (LCL) Collateral Ligaments. The knee is comprised of the bottom end of the femur (thigh) and the upper end of the tibia (shin) and the patella (knee cap).
The muscles which act at the knee are predominantly the quadriceps (extension) and the hamstrings (flexion). Being a hinge joint, it is structured to perform two principal actions – flexion (bending) and extension (straightening). The knee is one of the most complex joints in the human body.
