Knee and Thigh Flashcards
What does the mechanical load-bearing axis refer to?
weight bearing; the path of force bearing starting the the centre (widest) part of the femoral head to the foot (talus)
What is the hip knee angle? (MAT and MAF)
MAF= mechanical axis of the femur (start of femoral head and goes to centre of the femoral condyles, intercondylar notch) MAT= mechanical axis of the tibia (from midpoint of tibial spines to the centre of the talus)
What is the anatomical axes?
lines along the shafts- femur and tibia
What is genu recurvatum?
deformity in the knee joint, so that the knee bends backwards (excessive extension occurs at the knee joint)
What are the bones involved in the knee joint?
femur, tibia, fibula, patella
What are joints in the knee joint?
tibiofemoral joint, patellofemoral joint, superior tibiofibular joint
What are fat pads?
space filler in areas that change shape a lot and avoid the patella ligament or other things getting impinged
What does the tibiofemoral joint consist of?
femoral condyles and tibial plateau
What is the joint classification of the tibiofemoral joint?
bicondylar (predominantly uniaxial)
What are the actions of the tibiofemoral joint?
mainly F-E in sagittal plane (coronal axes), and limited rotation around vertical axis
What is the screw-home mechanism?
medial rotation of femur on tibia tightens ligaments which essentially locks your femur and tightens your ligaments and your capsule; good stability
What is extensor moment?
flat surface of femoral condyles with tibia and stabilise joints
Why is the shape of femoral condyles important?
it is flat on flat in extension so it creates stability
What is the functions of the tibiofemoral menisci?
increase congruency/contact area between femoral condyles and tibial plateau; decreases stress; protects articular cartilage
Why is the tibiofemoral menisci needed?
discrepancy of the shape of femoral condyles and the flat tibial plateau so there is the fibrocartilage structure interposed to create better contact area; therefore same amount of load distributed over a great area= same force, over greater area means less stress
Why is it important for there to be fibrocartilage in the meniscus?
fibrocartilage is deformable without tearing as readily as hyaline cartilage (fibrocartilage protects underlying hyaline cartilage)
What is the differences between the medial and lateral meniscus?
medial- longer in anterior-posterior direction, larger posterior horn, more capsule attachment
lateral- more variable and mobile as it doesn’t have as much capsular attachment
When will you have greater contact between the femoral condyles and posterior horn?
Flexion (greater weight bearing of posterior horn in flexion)
Which meniscus provides greater coverage of its plateau? Consequences?
lateral gives greater protection to its tibial condyle. consequence- bigger medial femoral condyle and tibial condyle but don’t have as effective coverage of the tibial condyle of the articular surface on the medial meniscus
What are the tibiofemoral ligaments?
tibial collateral (medial) ligament, fibular collateral (lateral) ligament, anterolateral ligament, anterior cruciate ligament, posterior cruciate ligament, oblique popliteal
What does the tibial collateral ligament (medial) resist?
resists valgus
What does the fibular collateral ligament (lateral) resist?
resists varus
What does the anterolateral ligament resist?
resists tibial IR in 30 degrees F
What does the anterior cruciate ligament resist? what are the two fibre bundles?
fibre bundles: posterolateral band (PLB), anteromedial band (AMB)
resists anterior translation of tibia on femur, resists posterior translation of femur on tibia, resists valgus, will tighten in end range extension
What does the posterior cruciate ligament resist?
resists posterior translation of tibia on femur, resists femur moving forward on tibia
What are the muscles of the anterior thigh?
sartorius, rectus femoris, vastus intermedius, vastus lateralis, vastus medius
What are the muscles of the posterior thigh?
biceps femoris, semimembranosus, semitendinosus
What are the muscles of the posterior leg?
gastrocnemius, plantaris, popliteus
What are the medial thigh and knee muscles?
pes anserinus: sartorius, gracilis, semitendinosus
What are the lateral thigh and knee muscles?
tensor fascia latae- iliotibial band, biceps femoris
What structures (active and passive) provide resistance to anterior translation of tibia on femur?
ACL, menisci, hamstrings
What structures (active and passive) provide resistance to posterior translation of tibia on femur?
posterior tibial, PCL, menisci, quadriceps
What structures (active and passive) provide resistance to tibiofemoral hyperextension?
oblique popliteal ligament, ACL, PCL
What structures (active and passive) provide resistance to tibiofemoral valgus?
width of TF jt, TCL superficial>deep, ACL, PCL, semimembranosus, semitendinosus, sartorius, gracilis
What structures (active and passive) provide resistance to tibiofemoral varus?
width of TF jt, FCL, ACL, PCL, posterolateral capsule, menisci, ITB, popliteus
What structures (active and passive) provide resistance to IR of tibia on femur?
ACL, ALL, menisci, bicep femoris
What structures (active and passive) provide resistance to ER of tibia on femur?
ACL, menisci, semimembranosus, semitendiosus, popliteus, sartorius, gracilis
