76 - Knee Joint Flashcards
Joints within knee joint capsule
Femur with tibia (tibiofemoral)
Femur with patella (patellofemoral)
Type of joint that knee joint is
Modified hinge joint (rotation occurs during flexion)
When is knee most stable?
In extension.
Relative sizes of tibial and femoral condyles
Medial condyles are longer than lateral, in antero-posterior direction.
Medial femoral condyle also extends further medially (upwards)
Part of knee that bears the most weight
Medial femoral condyle
Name for lateral displacement of bones of the leg, relative to tibia
Genu valgum (knock-kneed)
Name for medial displacement of bones of the leg, relative to tibia
genu varum (bow-legged)
Inter-condylar notch contents
Anterior cruciate ligament
Articular surfaces on tibial plateau
Almost flat, two articular surfaces.
Two groups of structures attaching to the tibial plateau
Anterior and posterior cruciate ligaments Meniscal attachments (four of these, lateral and medial)
What attaches to the meniscal attachments of the tibial plateau?
Medial and lateral menisces of the tibial
Arrangement of attachments of horns of medial and lateral menisci to tibial plateau
Medial attach far apart.
Lateral attach close together
Supports of knee joint
1-4
1) Capsule reinforced by muscle
2) Cruciate ligaments (anterior, posterior)
3) Collateral ligaments (medial, lateral)
4) Menisci (medial, lateral)
When is the knee most susceptible to injury?
When flexed
Attachment of capsult of knee joint
Around articular margins
Incorporates patellofemoral joint and intracapsular structures (EG anterior, posterior cruciate ligaments, menisci)
Location of synovial membrane, relative to cruciate ligaments.
Cruciate ligaments develop posterior to knee, push into space between articular surfaces during development, pushing synovial membrane away.
Cruciate ligaments are extrasynovial
Are menisci intra- or extra-synovial?
Intrasynovial, but not lined by synovial membrane
Capsular reinforcements of the knee joint 1 2 3 4
Anteriorly - patellar tendon + retinacular fibres
Lateral - popliteus, biceps femoris, iliotibial tract
Medial – ‘pes anserinus’ tendons
Posterior – (oblique popliteal ligament - from semimembranosus muscle)
Muscle reinforcing knee laterally
Popliteus muscle
Pes anserinus
‘Goose’s foot’
Muscle insertions reinforcing medial knee joint
Sartorius, gracilis, bursa, semitendinous muscles
Attachments of PCL
Attaches to posterior tibia, attaches to medial femur
Attachments of ACL
Attaches to anterior tibia, passes to lateral femur
Ligament that can compensate for a weaker PCL
Meniscofemoral ligament
Primary role of ACL
Prevents tibia being displaced anteriorly, relative to femur
When is ACL taut?
In extension, but also full flexion
Composition of ACL
Two fibres: anteromedial and posterolateral