Knee Anatomy
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Transcript of Knee Anatomy
Knee Anatomy
Knee Joint
• The most poorly constructed joint in the body. Femur round, tibia flat.
• Comprised of four bones.– Femur– Tibia– Fibula– Patella
Femur
• Medial and Lateral Condyles- distal ends of the femur.
• Largest bone in the body
Femur
• Landmarks to know• Add. Tubercle• Medial and Lateral
epicondyles• Medial and lateral
condyles• Intercondylar fossa• Patella fossa (not
shown)
Tibia and Fibula
Fibula
• Landmarks to know• Apex• Head• Neck• Lateral Maelleolus
Tibia
• Landmarks to know
• Intercondylar eminence
• Medial and lateral condyles
• Tibial tuberosity
Patella
• Patella tendon- attaches to the anterior of the tibia. (tibial tuberosity)
• Quadriceps tendon-attaches the quadriceps to the patella.
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
Knee Stabilizers
• PRIMARY– Medial Collateral
Ligament– Lateral Collateral
Ligament– Anterior Cruciate
Ligament– Posterior Cruciate
Ligament
• SECONDARY– Medial Meniscus
• “C” shaped
– Lateral Meniscus• “O” shaped
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
ACL
• Has Two Bundles– Anteromedial
•Tight in flexion and extension
– Posterolateral•Tight in extension
• Ligament is most lax between 30 – 60 degrees flexion
Posterior Cruciate Ligament
• Prevents posterior translation of the tibia on the femur
• Resists hyperextension of knee
• Runs from posterior tibia to anterior femur
PCL
• Fibers are tightest around 30 degrees flexion– Posterolateral fibers are the last
to become tight
• Two times stronger than ACL
Collateral Ligament
• Medial Collateral Ligament (MCL)- connect the tibia and the femur.
• A force from the lateral side could cause a tear.
• Valgus force
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
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
Lateral Collateral Ligament
• Attaches to head of fibula
• Prevents excessive varus and IR forces
• Tightest in extension, loosest after 30 degrees flexion
Cartilage
• Articulate Cartilage-covers the moving parts of the knee.
• Chronic damage to articulate cartilage leads to arthritis.
Cartilage
• Meniscus- half moon shaped cartilage lying between the knee joint.
ARTICULAR DISCS
• Medial Meniscus
• Lateral Meniscus
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?
Meniscal Blood Supply