G&F - Knee Joint
Card Set Information
G&F - Knee Joint
Gross & Functional (knee)
T/F - The knee joint is the most frequently injured joint in the body
What is the largest joint in the body?
The knee joint is classified as what kind of joint?
synovial hinge joint
What are the possible motions of the knee joint?
- Flex 125-130
- Ext - 0 degrees
What is genu recurvatum?
beyond 5 degrees of hyperextension
Why isn't the knee joint a true hinge joint?
It has a rotational component
Is the rotational component of the knee joint a free motion?
No - it is a accessory motion accompanying flex-ext.
The femur must glide postieriorly on the __________ as it rolls into __________
The weight bearing extension of the knee is what kind of action?
closed chain action
The weight bearing extension of the knee causes the femur to do what?
spin (rotate medially) on the tibia
The non-weight bearing extension of the knee is what kind of action?
open chain action
The non-weight bearing extension of the knee causes the tibia to do what?
rotate laterally on the femur
What is the screw home mechanism?
- occurs in the last few degrees of motion to lock the knee
- with the knee fully extended an individual can stand for a long period of time w/o using mm
The small amount of rotation of the femur on the tibia, or vice versa, prevents the knee from being what?
true hinge joint
What is the patellofemoral joint?
smooth posterior surface of patella glides over the patellar surface of the femur
What are the 2 main functions of the patella?
- increasing mechanical advantage of the quadriceps mm
- protecting the knee joint
What is the moment arm?
perpindicular distance b/t the muscle's line ofa ction and the center of the joint (axis)
The action line of the quadriceps muscles is farther away if the patella is placed where?
b/t the quadriceps, or patellar tendon, and the femur
The muscles in the knee have greater angular force when the moment arm does what?
The moment arm would be shorter and most of the mm force would be a stablizing force directed back into the joint if what was absent?
What is the Q Angle and where is it?
- patellofemoral angle
- b/t the quadriceps muscle, rectus femoris, and the patellar tendon
How do you determine the Q Angle?
draw a line from the asis to midpoint of patella and tibtub to the midpoint of the patella
In knee extensions, the Q Angle is within what range?
13 to 19 degrees
Why is the Q Angle normally greater in females than in males?
because female pelvis is usually wider
Where does the sesamoid bone form?
What bone is amechanical advantage of lever arm?
What is the knee composed of?
the distal end of the femur articulating with the proximal end of the tibia
How does the fibula relate to the tibia?
- it is lateral to and smaller than the tibia
- it is set back from the anterior of the surface of the tibia allowing for larger space for mm attachment
Why isn't the fibula part of the knee joint?
it doesn't articulate with the femur and has a larger role at the ankle
What is the patella?
triangular sesamoid bone w/in the quadricep muscle tendon
What is the most posterior tarsal bone?
What do the cruciate and collateral ligaments do?
help hold the knee together
What are cross cruciates?
these are located w/in the joint capsule and are called intracapsular ligaments
Where are cruciate ligaments situated?
b/t the medial and lateral condyles
Where is the anterior cruciate ligament?
it runs from the anterior surface of the tibia (under the patella) to the posterior femur
Cruciates provide stability where?
What is the function of the ACL?
- keeps the femur from being displaced posteriorly and on the tibia
- keeps the tibia fro being displaced anteriorly on the femur
How does the ACL prevent excessive hyperextension of the knee?
it tightens during extension
When does the ACL keep the tibia from moving anteriorly?
when the knee is partly flexed
Where is the posterior cruciate ligament located?
runs from the posterior tibia to the anterior femur
What is the function of the PCL?
- keeps the femur from displacing anteriorly on the tibia
- keeps the tibia from displacing posteriorly on the femur
When does the PCL tighten?
Which is injured more frequently, the ACL or the PCL?
What ligaments are located on the side of the knee?
medial collateral liagment & lateral collateral ligament
Collateral ligaments provide stability where?
Collateral ligaments tighten during what?
Collateral ligaments loosen during what?
What is the MCL also known as?
tibial collateral ligament
What is the shape of the MCL?
flat broad ligament
Where does the MCL attach?
to the medial condyles of the femur and tibia
The fact that fibers of medial meniscus are attached to this ligament contribute to what kind of injury?
frequent tearing of the medial meniscus during excessive stress to MCL
What is the LCL also known as?
fibular collateral ligamet
What is the LCL shaped like?
round cord like ligament
Where does the LCL attach?
to the lateral condyle of the femur and runs dow to the head of the fibula
The MCL provides medial stability and prevents excessive motion if what occurs?
a blow to the lateral side of the knee
What does the LCL protect the knee joint from?
stresses to the medial side of the knee
What are located on the superior surface of the tibia?
medial and lateral menisci
What are the menisci shaped like?
2 half moon wedge shaped fibrocartilage disks
what are the menisci designed to do?
Why are the menisci thicker laterally than medially?
because the proximal sufaces are concave
The menisci deepen what?
the relatively flat joint surface of the tibia
Which menisci is torn more frequently?
What are the 2 types of end feel at the knee joint?
- knee flexion soft
- knee extension firm
What is the knee flexion soft?
- soft tissue approximation
- from mm bellies of thigh and leg touching each other
What is knee extension firm?
soft tissue stretch due to tensin of the joint capsule and ligaments
How many bursa are located at the knee joint and why?
13 - to reduce friction
Why are bursa needed in the knee joint?
many of the tendons around the knee joint have a mostly vertical line of pull against bony areas or other tendons
What is the popliteal space?
area behind the knee that contains important nerves & blood vessels
What are located in the popliteal space?
- tibial, common, & peroneal nerves
- politeal artery & vein
where is a good place to measure pulse in the knee?
popliteal space on the politeal artery/vein
What are the One Joint MM?
- vastus lateralis
- intermdius biceps femoris short head
- popliteus (unlocks the knee)
What are the Two Joint MM?
- rectus femoris
- biceps femoris long
What is genu valgum (knock knees)?
distal segements (ankles) are positioned more laterally than normal causing the knees to touch while the ankles are apart
What is genu varum (bowlegs)?
the ankles are more medially than normal causing the ankles to touch while the knees are far apart
Coxa valgus is often seen with what?
coxa varus is often seen with what?
What is patellar tendonitis (jumper's knee)?
tenderness at the patellar tendon caused by overuse stress from jumping
Who often suffer from patellar tendonitis?
- bb players
- high jumpers
What is osgood schlatter disease?
overuse injury in adolescents involving traction type epiphysis
What is patellofemoral pain syndrome?
problem causing diffuse anterior pain resulting from increased Q angle, patella alta, quad weakness or tighness, weakness of hip lateral rotators, and excessive foot pronation
What is terrible triad?
knee injury caused by a single blow to the knee and involves tears to the ACL, MCL, and medial meniscus
What is miserable malaligament syndrome?
alignment of the lower extremity involving increased anteversion of the femoral head
What is miserable malaligament syndrome associated with?
- genu valgus
- pronated flat foot
- increased tibial torsion
Diamond shaped is bound superior medially by what?
semiten - semimem
Diamond shaped is bound laterally by what?
Diamond shaped consists of the infeior lat med heads of what?
Pes Anserine (goose's foot) is made up of what?