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Unformatted text preview: LECTURE # 14: Knee (Anatomy) • Large synovial joint • Modified hinge joint due to size differences of femoral condyles (medial larger than lateral) • “screw-home” mechanism – unlocked by popliteus o Knee locked out in full extension o Most stable o Medial femoral condyle continues to role and slides posterior after lateral condyle has stopped Ligaments • ACL – Anterior Cruciate Ligament – injured by deceleration; work on hamstring after injury o Main stabilizer o 2 bundles twisted together o O: anterior, medial aspect of intercondular notch (shallower in females) of tibia o I: lateral femoral condyle o A: resist anterior displacement of tibia in relation to femur, hyperextension and internal rotation • PCL – Posterior Cruciate (cross) Ligament – injured by getting hit below knee or falling with plantarflexion o O: posterior tibia o I: medial femoral condyle o A: resist posterior displacement of tibia in relation to femur ACL and PCL are intracapsular…means you get effusion swelling. MCL and LCL are capsular…means you get edema swelling. • MCL – Medial Collateral Ligament (on the meniscus) o O: medial epicondyle of femur o I: medial tibial plateau (3 fingers below the joint line) o A: resist valgus stress; if you have severe valgus stress…can injure meniscus) • LCL – Lateral Collateral Ligament o O: lateral epicondyle of femur o I: fibular head o A: resist varus stress Meniscus • Fibrocartilage discs (lie on tibial condyles) • Medial is more C shaped, larger in diameter, and firmly attached to tibia (more commonly torn) • Lateral is more O shaped, thicker, and more mobile • Change shape through ROM • Will not heal itself • Functions: cushion, shock absorption, stability Patella (Anatomy) • Patella – increases the pull of the patellar tendon allowing for greater force production; sesamoid and intertendonous o Position maintained laterally by the retinaculum o Position maintained medially by VMO o Poor tracking occurs when there is an imbalance • Patella Positioning o Patella Alta – high riding patella o Patella Baja – low riding patella – more prone for patella tendonitis...
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- Fall '09
- Psychology, Medial collateral ligament, LATERAL COLLATERAL LIGAMENT, Medial femoral condyle, patella o Patella, special test