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Ch. 18 The Knee. Objectives. Describe the functions of the knee Describe the ligament structure of the knee Explain the function of the patellofemoral joint List and define various sports-related injuries of the knee. Bones. Femur Medial and lateral condyles Tibia Tibia plateau
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Objectives • Describe the functions of the knee • Describe the ligament structure of the knee • Explain the function of the patellofemoral joint • List and define various sports-related injuries of the knee
Bones • Femur • Medial and lateral condyles • Tibia • Tibia plateau • Patella • Largest sesamoid bone in the body
Joints • Tibiofemoral joint is a hinge joint composed of a joint capsule and several ligaments • Main motions are flexion and extension • Patellofemoral joint is the articulation between the patella and femur • Gives greater mechanical advantage in knee extension • Increases quadriceps force by 33% to 50%
Cartilage • Articular cartilage covers ends of both tibia and femur • Menisci are located between femoral condyle and tibial plateau • Shock absorption, force distribution, improve stability • Synovial membrane and fluid
Collateral Ligaments • Medial collateral ligament (MCL) • Attaches femur to tibia • Lateral collateral ligament (LCL) • Attaches femur to fibula • Provides medial and lateral stability of the knee
Cruciate Ligaments • ‘Cruciate’ means cross • Anterior cruciate ligament (ACL) • restricts anterior translation of tibia • Posterior cruciate ligament (PCL) • restricts posterior translation of tibia • Both control rotation and help with stability
Muscles • Quadriceps • Vastusmedialis • Vastuslateralis • Vastusintermedius • Rectus femoris • Powerful knee extensor • Forms patella tendon which attaches to tibia at tibial tubercle
Muscles • Hamstrings • Biceps femoris • Semimembranosus • Semitendinosus • Activated during knee flexion • Semitendinosus tendon used during ACL repair
Muscles • Pes Anserine-assist with knee flexion • Sartorius • Gracilis • Semitendinosus • Sartorius is the longest muscle in the body