W26-L4: Knee Joint Flashcards
What are the two joints within the knee joint?
- Tibiofemoral
- Patellofemoral
What is the closed pack position of the knee?
Extension
T/F Articular surfaces provide a large amount of support
False, mainly from ligaments and menisci
What 3 pairs of structures provides the major support to the knee?
- cruciate ligaments (ant & post)
- collateral ligaments (med & lat)
- menisci (med & lat)
What is the difference between the medial and lateral condyles of the tibia and femur?
Medial condyles of both tibia & femur are longer than lateral
What happens in knee extension to the femur?
- Rotates medially on fixed tibia, passive process
- occurs about a tight ACL in the last 15-20 degrees, then in full extension all ligaments are tight
What happens in knee flexion to the femur?
- Requires active contraction of popliteus
- Femur rotates laterally on a fixed tibia
How does the synovium and capsule line the ACL and PCL?
only synovial
membrane on anterior surface (intra-capsular but extra-synovial)
What the reinforcements to the knee capsule?
- Anterior: Patellar tendon, retinacular fibres
- Lateral: Popliteus, biceps femoris, iliotibial tract
- Medial: ‘pes anserinus’ tendons
- Posterior: Oblique popliteal ligament
What are the deficiencies in the capsule?
- above patella for suprapatellar bursa
- posterior for popliteus tendon
Where does the ACL run?
From anterior of tibia to lateral femur
Where does the PCL run?
From posterior of tibia to medial femur
What does ACL oppose?
Stops femur moving backwards and tibia moving forward
What does PCL oppose?
stop femur moving forwards and tibia moving
backwards
When does ACL injury occur?
Rotation occurs in the opposite direction (laterally) when there is knee extension
