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Unformatted text preview: for hip ADduction and assist for hip flexion.
– ADductors may also function as internal rotators Hip ABductors (Lateral Muscles) – Gluteus Medius anterior, middle, and posterior portion; all prime movers for ABduction.
– Gluteus Minimus prime mover for Abduction; stabilizes pelvis against gravity. Hip External
Rotators The Knee Complex
Review Anatomical Review
Bones of the Knee Complex Femur – Medial femoral condyle and lateral femoral condyle
– Patellar surface separates the condyles anteriorly and is a shallow, saddle shaped groove. Tibia – Lateral and medial condyles. Medial condyel provides 50% more articulating surface with femur than lateral tibial plateau. Patella – Largest sesamoid bone in the body. Fits anteriorly against the femur where it is anchored by ligaments and the tendon of the quadriceps. Anatomical Review
Joints of the Knee Complex Tibiofemoral joint articulation of the distal femur and the proximal tibia.
Patellofemoral joint articulation of the patella and the femur.
Superior tibiofibular joint proximal articulation of the tibia and fibula.
The knee joint is a modified hinge joint, allowing flexion and extension in a sagittal plane around a “X” axis. It also allows a slight amount of rotation. Stability of the Knee Complex:
– accessory structures of each condyle.
Two asymmetric, wedgeshaped fibrocartilaginous joint discs located on the tibial plateaus. – Medial meniscus more prone to injury because it is firmly attached to the tibia and joint capsule. – Lateral meniscus moves more freely, more flexible, and so less prone to injury. Stability of the Knee Complex:
Ligaments Cruciate Ligaments Anterior cruciate ligament (ACL)
– arises from anterior surface of tibia, runs superiorly and posteriorly to attach on inner aspect of lateral femoral condyle.
ACL Posterior cruciate ligament (PCL)
– arises from the posterior aspect of the tibia and runs superiorly and anteriorly to attach to anterior portion of the inner aspect of medial femoral condyle.
PCL Collateral Ligaments
Collateral Reinforce medial and lateral aspects of the knee.
Medial Collateral (MCL) resists valgus stresses, runs from tibia to femur.
Lateral Collateral (LCL) resists varus stresses, runs from fibula to femur. Patellar Ligament
AKA Patellar Tendon
AKA Patellar Tendon Attaches the patella to tibia inferiorly. Patella is attached to the femur superiorly by the quadriceps tendon. Encloses Joint Capsule tibiofemoral and patellofemoral joints Large and lax with many communicating bursa.
Bursae Mobility of the Knee Complex
Mobility Flexion and extension result from rolling, spinning, and sliding of femoral condyles on tibial plateau.
– During flexion (closed
chain) femur needs to slide anteriorly & roll posteriorly
– During extension (closed
chain) femur needs to slide posteriorly & roll anteriorly Mobility of the Knee Complex (cont’d)
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- Fall '13