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The knee is the large lower extremity joint connecting the femur and the tibia. The knee supports nearly the entire weight of the body and is vulnerable to both acute injury and the development of osteoarthritis.

Anatomy and structure of the knee

The knee is a complex synovial joint that hovers and actually is comprised of two separate joints. The femoral-patellar joint consists of the patella, or "kneecap," which sits within the tendon of the anterior thigh muscle and the patellar groove on the front of the femur through which it slides.

On the other hand, the femoral-tibial joint links the femur, or thigh bone, with the tibia, the main bone of the lower leg. The joint consists of a viscous fluid which is contained inside the "synovial" membrane, or joint capsule. Behind the knee is called the popliteal fossa.

Furthermore, the knee bones are connected to the leg muscles by several tendons that move the joint. Ligaments join the bones and provide stability to the knee. Some of the specific structures of the knee are as follows:

  • Femur: Thigh Bone

  • Tibia: Shin Bone (Main lower leg bone)

  • Fibula: Calf bone

  • Patella: Knee Cap

  • Anterior Cruciate Ligament: Prevents the femur from sliding back on the tibia and vice versa - the tibia sliding forward on the femur.

  • Posterior Cruciate Ligament: Prevents the femur from sliding forward on the tibia and the tibia from sliding backward on the femur.

  • Medial and Lateral Collateral Ligaments: Prevent the femur from moving from side to side.

  • Medial and Lateral Menisci: Two C-shaped pieces of cartilage that act as shock absorbers between the femur and tibia.

  • Bursae: Fluid-filled sacs that make the knee move smoothly.