knee joint Flashcards
patella
sesamoid bone
stable knee config
extended position
patellar lig & patella
strengthens the capsule anteriorly
fibular and collateral ligs
strengthen lateral and medially
arcurate and oblique popliteal ligs
strengthen posteriorly
pes anserinus
strengthens anterior medially
IT band
strengthens laterally
suprapatellar bursa
keeps quads from rubbing against patella
popliteus bursa
separates tendon of popliteus from lateral condyle
gastroc bursa
seps med head of gastroc from med femoral condyle
prepatellar bursa
seps skin from patella
subcutaneous
seps skin from tibial tuberosity
clergymans bursitus
inflammation of subcutaneous bursa
housemaids knee
inflammation of prepatellar bursa
deep infrapatellar bursae
seps patellar lig from tibial tub
normal knee alignment
slight valgus, 170 degrees opened laterally
Q angle
line drawn btw ASIS and center of patella and tibial tub
15-20 degrees, larger in women
too big, patella can track laterally
genu valgum
knock knee, angle btw tib and femur is less than 170
genu varum
bow leg, angle is more than 170
MCL
has a deep insertion on med meniscus
maintains knee in extended position
resists valgus forces
LCL
not as strong as MCL
maintains entended knee
resists varus forces
not part of fibrous
ACL
resists ant mvmt of tib on femur
PCL
resists post forces of tib on femur
menisci
shock absorbers
tears cause locking of the knee, clicking
lateral meniscus
mobile, not attached to LCL, less likely to be injured
med meniscus
attached firmly to the med condyle
C shaped
less mobile, more likely to be injured
post horn much bigger than ant
abduction injury
valgus force/lateral blow to knee, tears med meniscus
final screw home mvmt
tib rotates laterally on femur
max contact btw tib and femoral condyles
locking knee
locked knee
all 4 ligs taut, prevents hyperextension
unlocking of the knee
popliteus muscle
WB: rotates the femur laterally on tib
NWB: medially rotates tibia on femur
ligs go lax, flexion occurs
knee flexors
hamstrings
inward rotators (when flexed)
pes anerinus
outward rotators (when flexed)
biceps femoris
ACL tear
sudden stopping of forward motion
anterior draw sign
lachman test: more specific
PCL tear
foot gets stuck while femur is forced backward
less often damaged
post draw sign
MCL tear
more common than LCL injury
lateral (valgus) stresses tear it
LCL tear
medial (varus) stresses
medial menisci tear
often caused by MCL tear
McMurray test: posterior horn tear assessment, clicking when rotating flexed knww with patient supine
unholy triad
medical meniscus, MCL, and ACL likely to all get injured together from post lateral blows to the knee
femoral nerve lesion
wasting of ant comp of thigh muscles. cant walk up or down stairs or stand or sit up unassisted
sciatic nerve lesion
paralysis of hamstrings, cant flex knee or extend hip
L2L3 root damage
weak quads
concentric contractions: hard time standing from seated, walking up stairs
eccentric: sitting from standing, walking down stairs