1. Knee Anatomy

2. Knee Joint • The most poorly constructed joint in the body. Femur round, tibia flat. • Comprised of four bones. • Femur • Tibia • Fibula • Patella

3. Femur • Medial and Lateral Condyles- distal ends of the femur. • Largest bone in the body

5. Femur • Landmarks to know • Add. Tubercle • Medial and Lateral epicondyles • Medial and lateral condyles • Intercondylar fossa • Patella fossa (not shown)

6. Tibia and Fibula

9. Fibula • Landmarks to know • Apex • Head • Neck • Lateral Maelleolus

10. Tibia • Landmarks to know • Intercondylar eminence • Medial and lateral condyles • Tibial tuberosity

11. Patella • Patella tendon- attaches to the anterior of the tibia. (tibial tuberosity) • Quadriceps tendon-attaches the quadriceps to the patella.

12. Joints • Tibiofemoral • Largest joint in body • Patellofemoral • Patella contains the thickest cartilage found in the body • Superior Tibiofibular • Any movement here is due to movement at the ankle

13. PRIMARY Medial Collateral Ligament Lateral Collateral Ligament Anterior Cruciate Ligament Posterior Cruciate Ligament SECONDARY Medial Meniscus “C” shaped Lateral Meniscus “O” shaped Knee Stabilizers

14. Cruciate Ligaments • Major stabilizing ligaments in the knee • Anterior Cruciate Ligament (ACL)-prevents the tibia from sliding out in front of the femur • Injuries caused by hyperflexion, internal rotation, hyperextension

16. ACL • Has Two Bundles • Anteromedial • Tight in flexion and extension • Posterolateral • Tight in extension • Ligament is most lax between 30 – 60 degrees flexion

17. Posterior Cruciate Ligament • Prevents posterior translation of the tibia on the femur • Resists hyperextension of knee • Runs from posterior tibia to anterior femur

18. PCL • Fibers are tightest around 30 degrees flexion • Posterolateral fibers are the last to become tight • Two times stronger than ACL

19. Collateral Ligament • Medial Collateral Ligament (MCL)- connect the tibia and the femur. • A force from the lateral side could cause a tear. • Valgus force

20. Medial Collateral Ligament • Two layers • Deep layer is actually a thickening of the joint capsule that blends into the medial meniscus • Superficial layer is what we view as the MCL

21. Collateral Ligament • Lateral Collateral Ligament (LCL)- connect the fibula to the femur. • A force from the medial side can cause a tear of the LCL • Varus force

22. Lateral Collateral Ligament • Attaches to head of fibula • Prevents excessive varus and IR forces • Tightest in extension, loosest after 30 degrees flexion

23. Cartilage • Articulate Cartilage-covers the moving parts of the knee. • Chronic damage to articulate cartilage leads to arthritis.

25. Cartilage • Meniscus- half moon shaped cartilage lying between the knee joint.

26. ARTICULAR DISCS • Medial Meniscus • Lateral Meniscus

27. Meniscal Blood Supply • Each Meniscus has 3 zones • Red Zone • Outer 1/3: good blood supply • Red/White Zone • Middle 1/3: minimal blood supply • White Zone • Inner 1/3: avascular (no blood supply) • Implications for injury?

28. Meniscal Blood Supply