The knee joint is one of the largest joints in the body. It is a complex joint with four bones: the femur (thigh bone), the tibia (main lower leg bone), the fibula (smaller lower leg bone), and the patella (kneecap). The bones are connected with four main ligaments: ACL (anterior cruciate ligament), PCL (posterior cruciate ligament), MCL (medial collateral ligament), and the LCL (lateral collateral ligament).
The ACL and PCL control the forward/backwards movement of the knee joint and prevent pivoting of the knee. The MCL and LCL prevent giving away on either side of the knee. The quadriceps is a group of 4 muscles that converge on the front of the thigh and together allow one to straighten their knee by pulling through the kneecap and patellar tendon, which attaches to the front of the lower leg bone (tibia).« Back to Glossary Index