The knee is a hinged joint and is comprised of several structures.
The femur (thigh bone - the largest bone in your body) extends from the hip to the knee joint. The tibia (shin bone - lower leg bone) connects to the knee joint also, and this area is covered by the patella (kneecap).
Articular cartilage covers the bone ends of the femur and the tibia and assists it in allowing for a gliding motion in the joint. The menisci (lateral and medial meniscus) make up a “C” shaped cartilage that forms an actual cushion inside the joint, thus providing shock absorption.
The bones are tethered, or bound together, by supportive ligaments (anterior cruciate, posterior cruciate). Surrounding muscles help move the joint, decrease stress on the joint, and provide additional support. Support and stability in the knee are provided by its four ligaments.
How the Knee Works
The fibrocartilaginous menisci of the knee are firmly attached to the tibia anteriorly and posteriorly but are only loosely attached peripherally. During normal knee movement, they tend to move slightly inward or outward. Normal knee movement consists of a combination of movements (rotation, extension and flexion). These movements are controlled by the ligaments of the knee and by the menisci, which also aid in shock absorption.