the knee and related structures Flashcards
bones of the knee
femur, tibia, fibula, patella
meniscus
two semilunar fibrocartilages that deepen the articular facets of the tibia, cushion any stresses placed on the knee joint and maintain spacing between the femoral condyles and tibial plateau
also help to stabilize the knee especially the medial meniscus which helps to stabilize at 90 degrees of knee flexion
meniscus blood supply
middle genicular artery provides nourishment to outer 1/3 of meniscus
inner 2/3 is avascular– receives nourishment from synovial fluid
red red zone
outer 1/3 layer with good vascular supply
red white zone
middle 1/3 layer has minimal blood supply
white white
inner 1/3 layer and is avascular
Anterior cruciate ligament
3 bands: anteromedial, intermediate, posterolateral
prevents femur from moving posteriorly during weight bearing and limits anterior translation of the tibia in non-weight bearing.
stabilizes the tibia against excessive internal rotation and serves as a secondary restraint for valgus and varus stress with ligament damage
posterior cruciate ligament
taut throughout the full ROM
resists internal rotation of tibia, prevents hyperextension of the knee, limits anterior translation of the femur during weight bearing and limits posterior translation of tibia during non-weight bearing
medial collateral ligament
prevents valgus and external rotation forces
blends with semimembranous and posterior medial meniscus
lateral collateral ligament
a ligament that attaches to the femur and the fibula; maintains stability of the lateral aspect of the knee joint
taut in extension relaxed in flexion
stabilizes lateral knee alongside ITB, popliteus and biceps femoris
knee bursas
suprapatellar, prepatellar, infrapatellar, superior infrapatellar, deep infrapatellar, pretibial, gastroc bursae
quad muscles
rectus femoris, vastus lateralis, vastus medialis, vastus intermedius
O: ASIS, greater trochanter, lateral/medial lip of linea aspera and anterior femur
I: tibial tuberosity via patella and patellar ligament
A: knee extension
N: femoral (L2-4)
hamstrings
biceps femoris, semitendinosus, semimembranosus
O: ischial tuberosity (short head biceps lateral linea aspera)
I: lateral head of fibula (BF), pes anserine (SM/ST)
A: knee flexion and external rotation (BF) internal rotation (SM/ST)
N: sciatic and tibial
sartorius
O: asis
I: prox medial surface of the tibia below the tuberosity
A: knee flexion and internal rotation
N: femoral
popliteus
O: lateral condyle of the femur
I: posterior surface of the tibia below the plateau
A: flexion and internal rotation
N: tibia
gastrocnemius
lateral head O: posterior lateral condyle of the femur
medial head O: popiteal surface of the femur above the medial condyle
I: posterior surface of the calcaneus
A: knee flexion
N: tibial
nerve supply to knee
tibial, common peroneal, superficial peroneal
screw home mechanism
A phenomenon that increases knee joint stability by locking the femur on the tibia (or vice-versa) when the knee is fully extended.
patella alta
high riding patella
patella baja
low riding patella
genu valgum
knock knees
genu varum
bow legged
genu recurvatum
hyperextension of knee
meniscus tests
apleys, thessaly, mcmurrays, drop test
pcl tests
posterior drawer, sag sign
acl test
lachman, anterior drawer, pivot shift, jerk test, slocum, losee test
mcl/lcl
varus
valgus - test at 30 and 0
girth measurement
8-10 cm above joint line 2cm above patella joint line tibial tubercle belly of gastrocnemius
Q- angle
degree of angle when measuring from mid patella to ASIS and tibial tubercle through the center of the patella. normal q angle is 10 degrees for man and 15 degrees for a woman.
osgoode shlatter disease
stress on tibial tuberosity and distal patellar tendon
larsen-johansson disease
Disease similar to Osgood-Schlatter disease, but it occurs at the inferior pole of the patella.
