bones of the knee, the femur and the tibia, meet to form a
The joint is protected in front by the patella (kneecap). The knee joint is cushioned
by articular cartilage that covers the ends of the tibia and femur,
as well as the underside of the patella. The lateral meniscus and
medial meniscus are pads of cartilage that further cushion the joint,
acting as shock absorbers between the bones.
Ligaments help to
stabilize the knee. The collateral ligaments run along the sides
of the knee and limit sideways motion. The anterior cruciate ligament,
or ACL, connects the tibia to the femur at the center of the knee.
Its function is to limit rotation and forward motion of the tibia. (A
damaged ACL is replaced in a procedure known as an ACL
Reconstruction.) The posterior cruciate ligament, or PCL (located
just behind the ACL) limits backward motion of the tibia.