Knee joint is composed of three bones, two inside ligaments, two outside ligaments, and two menisci.
Three bones are femur (thigh bone), tibia (shin bone) and patella (kneecap).
The two inside ligaments are anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL).
The two outside ligaments are medial collateral ligament (MCL) and lateral collateral ligament (LCL).
The two menisci are medial and lateral meniscus.
Knee joint act as a hinged joint but in fact is not a true hinge. In addition to bending and extending like a hinge it has also a complex rotational movement when knee comes from bending (flexion) to a straight position (extension).
The knee joint is held together by it’s ligaments and muscles attached to it and is the major weight bearing joint in our body.
The end of the bones at the knee is covered with a thick layer of cartilage that provide shock absorption among other functions such as lubrication and nutrition.