Knee Anatomy

Question 1

Knee joint compartments

Answer 1

Tibiofemoral

• Comprised of the patella/femur joint, lateral and medial compartments (between femur condyles and tibia)
• Synovial membrane and cruciate ligaments partially separate the medial and lateral compartments

Patellofemoral

• Ligamentum patellae
• Actions: provides joint stability in full extension

Question 2

Fibrous capsule

Answer 2

Anterior fibres - The capsule does not pass proximal to the patella. It blends with the tendinous expansions of vastus medialis and lateralis

Posterior fibres - These fibres are vertical and run from the posterior surface of the femoral condyles to the posterior aspect of the tibial condyle

Medial fibres - Attach to the femoral and tibial condyles beyond their articular margins, blending with the tibial collateral ligament

Lateral fibres - Attach to the femur superior to popliteus, pass over its tendon to head of fibula and tibial condyle

Question 3

Bursae

Answer 3

Anterior

• Subcutaneous prepatellar bursa (between patella and skin)
• Deep infrapatellar bursa (between tibia and patellar ligament)
• Subcutaneous infrapatellar bursa (between distal tibial tuberosity and skin)

Laterally

• Bursa between lateral head of gastrocnemius and joint capsule
• Bursa between fibular collateral ligament and tendon of biceps femoris
• Bursa between fibular collateral ligament and tendon of popliteus

Medially

• Bursa between medial head of gastrocnemius and the fibrous capsule
• Bursa between tibial collateral ligament and tendons of sartorius, gracilis and semitendinosus
• Bursa between the tendon of semimembranosus and medial tibial condyle and medial head of gastrocnemius

Posterior - Highly variable and inconsistent

Question 4

Ligaments

Answer 4

Medial collateral ligament - Medial epicondyle femur to medial tibial condyle (valgus stability)

Lateral collateral ligament - Lateral epicondyle femur to fibula head (varus stability)

Anterior cruciate ligament - Anterior tibia to lateral intercondylar notch femur (prevents tibia sliding anteriorly)

Posterior cruciate ligament - Posterior tibia to medial intercondylar notch femur (prevents tibia sliding posteriorly)

Patellar ligament - Central band of the tendon of quadriceps femoris, extends from patella to tibial tuberosity

Question 5

Menisci

Answer 5

Medial and lateral menisci compensate for the incongruence of the femoral and tibial condyles.
Composed of fibrous tissue.
Medial meniscus is attached to the tibial collateral ligament.
Lateral meniscus is attached to the loose fibres at the lateral edge of the joint and is separate from the fibular collateral ligament. The lateral meniscus is crossed by the popliteus tendon.

Question 6

Nerve supply

Answer 6

The knee joint is supplied by the femoral, tibial and common peroneal divisions of the sciatic and by a branch from the obturator nerve. Hip pathology pain may be referred to the knee.

Question 7

Blood supply

Answer 7

Genicular branches of the femoral artery, popliteal and anterior tibial arteries all supply the knee joint.