Final Exam: Knee
during the anterior drawer test, a compromised ligament is one that moves how far
>90mm
the (MCL/LCL) is more developed than the other. why is this important?
MCL because we experience more contact from the lateral side of the knee than the medial side.
from the tibia to the femur, the ACL moves from _____ to _____ and ____ to ______.
anterior to posterior, medial to lateral
which of the hamstrings is most medial? lateral? middle?
biceps femoris is most lateral, semitendinosus is in the middle, and semimembranosus is medial
what are the flexors of the kneee?
biceps, semitendinosus, and semimembranosis
genu valgum is increased by _______ femoral head angle
coxa varum
why is an extended knee more stable than a flexed knee?
due to increased contact area between femoral head and the condyles of the tibia
the stabilizing ligament of the knee typically attach to what on the femur?
epicondyles
the ACL is taught in _____
extension/hyperextension
in the knee, there is stability in what orientation? this is primarily stabilized by what?
extension; bony architecture
is there more internal or external rotation of the knee during flexion?
external rotation is doubled internal rotation
past 90 degrees, the patella contacts the "wings" of the _______ instead of the center.
femoral condyles
what bones are associated with the knee joint?
femur and tibia
when the knee is _____, the patella is pulled against the T/F joint.
flexed
any rotation about the transverse plain occurs when the knee is in what orientation?
flexion
the patella is in greatest contact area with the T/F joint in what knee orientation?
flexion
the PCL is taught in _____.
flexion/hyperextension
the Pes Anserinus is a group of 3 muscles that function as _____ and _____.
flexors and internal rotators
knock-kneed people have a ______ knee angle.
genu valgum
what are the excessive knee angles called?
genu valgum and genu varum
bow-legged people have a ____ knee angle.
genu varum
in general, the knee experienced greater torques than other joints due to what?
greater moment arms
the patella has a thick layer of _____ that aids in distributing compressive forces as well as stays strong with lots of ware from sliding.
hyaline
almost every ligament in the knee resists ______.
hyperextension
at the knee, there is no bony architecture to prevent ______.
hyperextension
both the collateral ligaments resist _______ of the T/F joint
hyperextension
the medial knee flexors can also produce _______ while the lateral knee flexors can produce _______ only while the knee is in ______.
internal rotation; external rotation; knee flexion
what is the function of the popliteus?
it unlocks the knee from full extension by internally rotating
the gastrocnemius has a secondary function of ________
knee flexion
the menisci of the T/F joint are wedge-shaped, meaning they are thicker on the _____ side.
lateral
genu valgum knee angles increase stress on what?
lateral meniscus and MCL
the patella is more subject to _____ tracking due to the common valgus angle. This increases ware on what?
lateral tracking; increase ware on lateral patella and lateral tendons
the most common patellar fracture is in what direction?
longitduinal
what is the problem with the ligament tests at the knee?
low loading forces so if the ligament is partially compromised, you probably won't be able to tell
LCL resists contact from what side of the knee?
medial
genu varum knee angles increases stress on what?
medial meniscus
what are the shapes of the two menisci?
medial: c-shaped, lateral: o-shaped
from the tibia to the femur, the PCL moves from ____ to ____ and ____ to _____.
posterior to anterior, and lateral to medial
The T/F axis of rotation moves _____ with flexion and _____ with extension
posterior; anterior
the popliteus originates on the ________ side and inserts on the __________ _________ so when it shortens, it pushes on the back side of the _____
posterior; anterior tibia; tibia
what are the functions of the P/F joint?
protects from anterior knee trauma and to increase quadriceps mechanical advantage.
the two muscles that act on the patella are ______ (superior) and ______ (inferior)
quadriceps; patellar tendon
what is the function of the PCL?
resist posterior tibial translation on the femur
the patella is the largest ____ bone in the body
sesamoid
the menisci act as _____
shock-absorbers
how can you offset lateral patella tracking?
strengthen vastus medialis, however, the ratio of quadricep activation in all exercises favors the vastus lateralis over the medialis making this hard to fix.
at 90 degree knee flexion, the moment arm is typically what length?
the length of the femur
what part of the menisci has good blood supply? what does this mean with menisci injuries?
the outer third has good vascularity, meaning if it is injured, it will repair itself. the inner two-thirds is almost avascular, so it will not repair itself.
what is the one knee flexor muscle that is not biarticulate?
the short head of the biceps femoris
what is the primary attachment site for the quadriceps and patellar tendon?
tibial tuberosity
what is the function of the menisci in the T/F joint?
to increase depth of the contact area between distal femoral head and tibial condyles, as well as acting as shock absorbers for compressive forces.
what is the function of the ACL?
to resist anterior tibial translation on the femur
as knee extensors, 80% of the extension force is produced by the _______ muscles of the quad.
uniarticulate
normally, the knee has a slight _____ angle
valgum
MCL resists (varus/valgus) loading
valgus
the LCL resists (varus/valgus) loading
varus
what are the three quadriceps muscles? which is biarcticulate?
vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris (biarticulate)
if the menisci are compromised, do you need to fix them in most cases?
yes, almost always
