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