Knee Flashcards
What are the three articulations at the knee?
medial femerotibial, lateral femerotibial and femeropatellar
What 2 mechanisms prevent lateral patellar displacement?
vastus medialis pulling medially, bony ridge on lateral femoral condyle
How do the collateral ligaments control rotation at the knee?
Taut when leg extended, slack when flexed therefore allowing rotation
What are the attachments of the fibular collateral ligament?
lateral epicondyle of femur, lateral surface of head of fibula
Separated from lateral meniscus by tendon of politeus.
What are the attachments of the tibial collateral ligament?
medial epicondyle of femur, medial condyle and superior part of medial surface of tibia.
Also attached to medial miniscus at centre.
Where does the anterior cruciate ligament attach?
anterior intercondylar area of tibia, posteromedial part of lateral condyle of femur
Where does the posterior cruciate ligament attach?
posterior intercondylar area of tibia, anterolateral part of medial condyle of femur
What is the function of the anterior cruciate ligament?
prevents anterior displacement of tibia on femur, prevents hyperextension of knee
What is the function of the posterior cruciate ligament?
prevents posterior displacement of tibia on femur, prevents hyperflexion of the knee, stabilizes flexed knee when weight bearing (walking down hill)
How is the anterior cruciate ligament damaged?
through hyperextension of knee or application of a force anteriorly
How is the posterior cruciate ligament damaged?
through landing on tibial tuberosity when knee is flexed
What injuries make up the unhappy triad?
torn anterior cruciate ligament,
torn medial collateral (tibial) ligament,
torn medial meniscus
How is the knee “locked” and what is the function of this?
as knee approaches full extension femur rotated a few degrees medially, this allows relaxation of thigh muscles when stood up. Unlocked through lateral rotation by popliteus.
What movements are possible at knee?
flexion/ extension
rotation-when knee is flexed, ant cruciate lig crosses over post during medial rotation therefore not a lot of medial rotation is possible
What are the menisci?
Crescentic plates of fibrocartilage, thicker at external margin, on articular surface of tibia. Deepens surface as plateus and condyles incongruent, acts in shock absorption, distributes weight evenly and assist in locking.
