Knee TIBIOFEMORAL joint Flashcards Preview

Functional Anatomy > Knee TIBIOFEMORAL joint > Flashcards

Flashcards in Knee TIBIOFEMORAL joint Deck (62):
1

Which femoral condyle is larger and extends more distally?

Medial

2

What is the classification of the tibiofemoral joint and how many DOF?

double condyloid joint; 3 DOF

3

Femoral condyles are ______ while tibial plateau is ______.

large
flat

4

During dynamic gait, the line of force shifts _________ to the knee joint center.

medially

5

During dynamic gait, there is _________ compression and ________ tensile/distraction force.

medial
lateral

6

In bilateral stance, describe the WB stress to the medial and lateral condyles?

equal

7

What important component increases with genu varum?

Adduction Moment

8

What are 4 important properties of the medial and lateral menisci?

1. increase joint congruence
2. distribute WB forces
3. reduce friction b/w tibia and femur
4. shock absorption

9

Medial meniscus shape and implication?

C-shaped
Less surface area coverage than lateral. susceptible to injury, especially because the medial compression

10

Lateral meniscus shape and implication?

4/5 of a circle
covers greater proportion of smaller lateral tibial surface

11

What is the relationship between thickness and region for the menisci?

thicker peripherally
thinner centrally

12

Translation is limited for medial meniscus due to

greater ligamentous and capsular restraints

13

The relative lack of mobility of the medial meniscus may contribute to

greater incidence of injury

14

What attaches the menisci anteriorly?

transverse ligament

15

What attaches patella to menisci?

anterior capsular thickenings called the patellomeniscal ligaments

16

What are the peripheral attachments of menisci to tibial condyle?

coronary ligaments

17

Which muscle attaches through capsular connections to the medial meniscus?

semimembranosus

18

What is the primary fxn of the MCL?

restrict motion of medial meniscus

19

What structures attach to the medial meniscus?

ACL (Anterior and posterior horns)
deep portion of the MCL

20

Which muscle attaches through capsular connections to the lateral meniscus? Implication?

popliteus; it restrains movement of the lateral meniscus

21

Removal of menisci the contact area in the tibiofemoral joint is ________. Results?

decreased contact area
increased joint stress
risk for damage of articular cartilage

22

Which part of the menisci have vascularity?

periphery; central portion is avascular

23

How does central menisci get nutrition?

depends on diffusion of synovial fluid which requires intermittent loading by WB or muscular contractions

24

Which part of the menisci is well innervated?

free nerve endings (nociceptors) and mechanoreceptors loacted in meniscal horns and vascular periphery

25

What is the close-packed position of the knee?

FULL EXTENSION
max bony congruence and ligament tautness

26

Most mobility of the joint when the knee is in what position?

FLEXION
periarticular passive structures tend to be lax (relative bony incongruence)

27

The capsule is reinforced posterolaterally by the ________ ligament and posteromedially by the ________ ligament.

aruate
posterior oblique ligament
(both restrain hyperextension)

28

MCL best restrains valgus motion when the knee is in which position?

extension --> MCL is taut in extension

29

Injury to the ACL most often occurs with which position?

WB: slight flexion and and tibia rotated either way

30

Does the anterior or posterior cruciate ligament resist greater loads? Why?

posterior can resist greater loads: more extensive attachment, short, wide, less oblique

31

In a deep squat, which component of the PCL is taut?

posteromedial bundle; it limits posterior displacement of the tibia

32

Which component of the PCL is taut in 90* flexion?

anterolateral bundle

33

Which component of PCL is taut in extension?

posteromedial bundle

34

Which ligament best restrains in flexion?

PCL: restraint to posterior displacement

35

Which ligament best restrains in extension?

ACL: restraint to anterior displacement

36

Which muscles can decrease strain on PCL when knee is flexed?

POPLITEUS and quds

37

Which muscles can decrease strain on ACL?

hamstrings and soleus

38

Does ITB resist displacement?

Resists anterior displacement with the help of LCL and popliteal tendon when knee is flexed

39

In flexion of femur in WB, the femoral condyles roll in which direction? What ligament "checks"?

posterior roll checked by ACL --> results in anterior translational force by ACL on femur

40

In extension of femur in WB, the femoral condyles roll in which direction? What ligament "check"?

anterior roll checked by PCL --> results in posterior translational force by PCL on femur

41

The menisci must remain under the femoral condyles to fxn in reducing friction and absorbing forces onto the small tibial plateau. How do menisci react to forces during flex/ext?

deformation allows menisci to remain under femoral condyles

42

With posterior deformation of menisci, which muscles contribute?

semimembranosus exerts post. pull on medial meniscus
popliteus exerts post. pull on lateral meniscus

43

How do menisci react to forces as knee moves into extension?

anterior deformation

44

How do menisci react to forces in flexion?

posterior deformation

45

The medial femoral condyle is distal to the lateral femoral condyle in an extended knee. This results in?

physiological valgus knee (in extension)
axis for flex/ext is obliquely oriented

46

Coupled motions about the obliquely oriented axis for flex/ext are?

valgus+extension
varus+flexion

47

What is the axis for axial rotation (IR/ER)?

medial tibial plateau --> the lateral tibial condyle rotates about the medial

48

Axial rotation is maximized in which position? Limited in which position?

maximized in 90* flexion
limited in full extension

49

What happens with forceful quad contraction when the knee close to full extension? Why?

anterior tibial translation (places stress on both anteromedial and posterolateral ACL bundles)
patella increases the length-tension relationship by increasing MA for quads

50

There is little to no anterior translation in which position? Why?

knee flexed >60*
because of influence of patella on quad MA and length-tension relationship

51

What muscles assist with knee extension in WB?

soleus and glut max

52

During WB, quads generate greater force as knee ___________ increases to control the increasing MA.

flexion

53

During NWB, quads generate greater force as knee __________ increases to overcome the increasing MA.

extension

54

What structures limit anterior tibial translation?

ACL
ITB
Hamstring
Soleus (in WB)
Glut max (in WB)

55

What structures limit posterior tibial translation?

PCL
meniscofemoral ligaments
quads
popliteus
medial and lateral heads of gastric

56

What structures limit valgus of tibia?

MCL, ACL, PCL
arcuate ligament
posterior oblique ligament
sartorius, gracilis, semitendonosis (pes anserine)
semimembranosus
medial head of gastroc

57

What structures limit varus of tibia?

LCL, ACL, PCL
ITB
Arcuate ligamanet
posterior oblique ligament
biceps femoris
lateral head of gastroc

58

What structures limit medial rotation of tibia?

ACL
PCL
posterior medial capsule
meniscofemoral ligament
biceps femoris

59

What structures limit lateral rotation of tibia?

posterolateral capsule
popliteus
sartorius, gracilis, semitendonosis (semitendinosus)
semimembranosus
MCL
LCL

60

Posterolateral instability?

damage to posterolateral joint capsule, popliteus, acrcute ligament can cause excessive lateral tibial rotation and posterior instability

61

Posteromedial instability?

Dame to posterior oblique ligament, medial hamstrings, MCL and posteromedial joint capsule

62

Anteromedial and anterolateral knee has dynamic support from what structure?

Extensor retinaculum - composed of fibers from quadriceps femoris muscle and fuses with fibers of joint capsule