Knee Flashcards
(34 cards)
function of swing phase
knee flexes to shorten lower extemity and helps to clear the foot
function in stance phase
knee in slight flexion for shock absorption, conservation of energy and transmission of forces through LE
Why does the knee rarely function independently
2/3 of the muscles that cross the knee also cross either the hip or the ankle
knock knees
genu valus
coxa vara
compression on lateral side
bow legs
genu varum, coxa valgum, compression on medial side
back knees , hyperextension
genu recurvatum
femur on tib
convex on concave- opposite -closed chain
tib on femur
concave on convex- same - open chain
function of meniscus
reduce compressive stress, provide stability, aid in lubrication, provide proprioception
motion of meniscus
glide ant with ext
glide post with flex
where is the blood supply of meniscus greatest
peripherally
compression forces on knee walking, ascending stairs?
3x, 4x
meniscus ______ the area of joint contact
triples
_________ increases peak contact pressure at knee by 230% and increase risk of arthritis
a complete lateral meniscectomy
damage to the medial side of meniscus can be bad why
MCL attaches there
arthrokinematics of closed chain
fib on tib - convex on concave - opposite
ext- ant. fib roll, post. fib slide
arthrokinematics of open chain in knee
tib on fib - concave on convex - same
ext- ant slide, ant roll
what is the screw home mechanism
w/ open chain, tib rolls ant, slides ant during ext and tib externally rotates 10 degrees
What is the screw home mechanism driven by? 3 things
shape of medial femoral condyle- it extends further ant. so tib follows lateral curved path into ext
tension in ACL
lateral pull of quad
NOTE popliteus unlocks
Ligament restraint in flexion
PCL
Ligament restraint in extension
ACL
Ligament restraint in axial rot
MCL LCL PCL ACL
ligament restraint in valgus
MCL primarily, ACL and PCL
ligament strain in varus
LCL primarily ACL and PCL