Knee anatomy, illustration. At right the patella (kneecap) has been removed from view. On the inside of the knee (right) is the medial collateral ligament (MCL), which connects the femur (thigh bone) and tibia (shin bone) and limits sideways movement. The fibular collateral ligament (FCL) performs the same function on the outside of the knee, by connecting the femur and fibula (calf bone). In the centre of the knee joint are the anterior cruciate ligament (ACL), and posterior cruciate ligament (PCL), which connect the femur and tibia. They prevent forwards and backwards movements (respectively) of the bones in relation to one another. Running horizontally across the joint are the menisci (medial meniscus at left and lateral meniscus at right), which act as shock absorbers for the knee. Illustration from 'Connais toi, toi meme' by Louis Figuier (1879).