Knee Joint Flashcards
What are the two joints in the knee joint capsule?
the tibiofemoral joint and the patellofemoral joint
What movements occur at the knee joint?
flexion, extension and rotation
What is the close packed position of the knee joint?
extension
What position must the knee joint be in for rotation to occur?
flexion
Which femoral condyle is longer and which is wider?
medial is longer, lateral is wider
What is contained in the notch in the lateral side of the intercondylar area of the femur?
the ACL
Is flexion and extension active or passive?
extension is passive, flexion is active
In which direction does the femur rotate on the fixed tibia in flexion?
laterally
Which ligament acts like an axis of rotation in extension and gets gradually tighter?
ACL
Which muscle unlocks the knee?
popliteus
What is the origin and insertion of popliteus?
originates on the popliteal surface of the tibia and inserts on the lateral condyle of the femur
In which direction does the femur rotate on the fixed tibia in extension?
medially
Does the synovial membrane cover the menisci?
no
Does the synovial membrane cover the cruciate ligaments?
partially
What reinforces the capsule anteriorly?
patellar tendon an retinacular fibres
What reinforces the capsule laterally?
popliteus, biceps femoris, iliotibial tract
What reinforces the capsule medially?
pes anserinus tendons
What reinforces the capsule posteriorly?
tendon of semimembranosus (which gives off the oblique popliteal ligament)
In the pes anserinus which two tendons have a bursa between them?
gracilis and semitendinosus
Does the suprapatellar bursa communicate with the joint?
yes
Does the bursa deep to popliteus communicate with the joint?
yes
Which non communicating bursae are located anterior to the knee?
pre patellar, superficial infrapatellar, deep infrapatellar
What are the attachments of the anterior cruciate ligament?
anterior part of the tibia to the lateral condyle of the femur
What are the attachments of the posterior cruciate ligament?
posterior part of the tibia to the medial condyle of the femur
What is the function of the anterior cruciate ligament?
stops the tibia from being displaced anteriorly
What is the function of the posterior cruciate ligament?
stops the tibia from being displaced posteriorly
When do patients with a posterior cruciate ligament injury feel instability?
while going down stairs
When is the ACL injured?
when femur is forced into lateral rotation on a weight bearing knee
When is the PCL injured?
fall on a flexed knee or a bumper bar impact pushing the femur posteriorly
What tests assess the ACL and PCL?
the anterior and posterior draw test
What are the two parts of the medial collateral ligament?
the long flat superficial part and the deep part which blends with the capsule and attaches to the medial meniscus
What is the role of the medial collateral ligament?
resist lateral movement of the tibia and resist anterior movement of the tibia if the ACL is damaged
What seperates the lateral collateral ligament from the lateral meniscus?
popliteus
What are the functions of the menisci?
shock absorption and weight distribution
Which menisci is more likely to be injured?
medial
Why does a meniscal tear sometimes cause a locked knee?
part of the torn off menisci may get stuck in the joint
Which mensici is bigger?
medial
Are the meinsci avascular or vascular?
vascular laterally and avascular medially
What 3 things maintain the normal alignment of the patellofemoral joint?
vastus medialis, medial patellar retinaculum, raised lip on lateral femoral condyle
What is chondromalacia patellae?
a patellar tracking problem which leads to degeneration of cartilage
Why are women more susceptible to patellar tracking problems?
because of the greater angle between the quadriceps tendon and the patellar tendon
