Knee joint Flashcards
Ligament of knee joint
collateral (tibial&fibular), cruciate (ant.&post.), meniscofemoral, oblique popliteal, arcuate
Nerve supply of knee
femoral+obturator (which also supplies hip), common fibular, tibial
What happens in patello-femoral dislocation
vastus medialis is much larger and counteracts the lateral pull of quadriceps resulting in lateral side of femur projecting forward
what is the Q angle and when does it increase
Angle between quadriceps tendon and patellar tendon in full extension. Angle between mechanical axis and shaft of femur.
Could increase in: genu valgum, increased femoral anteversion, external tibial torsion, laterally positioned tibial tuberosity, tight lateral retinaculum
What is function of meniscus in tibio-femoral knee joint
wedge shaped to keep femoral chondyle inside
cushions load and acts as shock absorber
meniscus used for weight distribution
What do tears of meniscus cause
if partial, reduces osteoarthritis risk
If parrot beak or bucket handle, joint can’t expand fully
How to tell medial and lateral chondyle of femur apart
Medial=short+curved
Lateral=short+straight
what do the collateral lig. of knees do
prevent twisting of knee joint, prevent too much movement side to side.
Ligaments of knee joint list and locate
fibular collateral ligament, tibial collateral lig., popliteus, iliotibial tract
What is genu varum and valgus caused by
varum=bow leg, Q angle <10deg
valgus=knock knee, Q angle >20deg
where are the cruciate lig. and what do they do
anterior=attach inside lateral femoral condyle
posterior=attach to medial femoral condyle
prevents anterior-posterior displacement of femur. If anterior ruptures, femur comes too far forward
How do the cruciate lig. work in extension and flexion
Extension: anterior taught, posterior should be relaxed but not taking rotation into account
Flexion: anterior relaxed, attachment point brought closer together, posterior taught
What does infrapatellar fat pad do
prevents synovial memb from droppign down behind ligamentum patellar tendon
What are the boundaries of the knee joint
ref. noes
Where are the bursae of knee joint
suprapatellar: extends 8cm above base of bursa
Popliteus: lies between popliteal and lateral condyle of tibia. Under popliteus tendon
Gastrocnemius: Under gastrocnemius tendon, behind knee joint, separates medial head of gastrocnemius and tibia
anserine: separates pes anserinus from tibia
