Knee Joint Flashcards Preview

MD1 Metabolism > Knee Joint > Flashcards

Flashcards in Knee Joint Deck (131):
1

How many joints share the capsule at the knee joint?

2

2

What are the two articulations of the knee joint?

Femur with tibia = tibiofemoral
Femur with patella = patellofemoral

3

What is the largest sesamoid bone in the body?

Patella

4

Why is the knee a modified hinge joint?

Have rotation when flexed, unlike normal hinge joint which only flexes and extends

5

What movement is required to flex the knee?

Rotation

6

What is the range of movement of the knee joint?

Relatively large

7

What is a close packed position?

Articular surfaces meet each other to greatest extent
Ligaments tight

8

What is the close packed position of the knee?

Extension

9

What is the loose packed position of the knee?

Midway through flexion

10

Why is the stability of the knee joint not from the bones?

Mismatch of shapes of articular surfaces: rounded femoral condyle articulating with flat tibial plateau

11

What gives the knee joint its stability?

Strong ligaments reinforcing capsule
Muscles attaching at joint

12

What is the notch between the femoral condyles?

Intercondylar notch

13

What is the nick in the intercondylar notch for?

Indentation of anterior cruciate ligament

14

What can cause erosion of the anterior cruciate ligament?

Narrow intercondylar groove (nick in intercondylar notch)

15

Which femoral condyle is longer, and by how much?

Medial femoral condyle longer by 1 cm

16

Which femoral condyle is wider?

Lateral femoral condyle

17

What action is the position of the anterior cruciate ligament very important for?

Hyperextension at knee > stand upright

18

Which femoral condyle bears the most weight, and what proportion is it?

Medial femoral condyle bears 75% of weight

19

Which femoral condyle undergoes more osteoarthritic changes?

Medial femoral condyle

20

With a valgus deviation, what is the change in weight bearing at the knee?

Lateral femoral condyle bears more weight than normal

21

What covers the tibial plateau in the medial and lateral aspects?

Articular cartilage

22

What covers the margins of the tibial plateau?

Menisci

23

What are the menisci made of?

Fibrocartilage

24

What do the menisci in the knee joint do?

Support femoral condyles

25

From anterior to posterior, what attaches to the central, raised part of the tibial plateau?

Anterior horn of medial meniscus
Anterior cruciate ligament medially, Anterior horn of lateral meniscus laterally
Posterior horn of lateral meniscus
Posterior horn of medial meniscus
Posterior cruciate ligament

26

What is the femoral attachment of the anterior cruciate ligament?

Lateral aspect of lateral femoral condyle

27

What is the femoral attachment of the posterior cruciate ligament?

Medial femoral condyle

28

What is the shape of the cruciate ligaments from the front?

Cross

29

What 3 pairs of non-muscular structures support the capsule at the knee joint?

Anterior and posterior cruciate ligaments
Medial and collateral ligaments
Medial and lateral menisci

30

When are the structural supports at the knee especially susceptible to injury?

In flexion and rotation

31

What is the extent of the capsule in the knee?

Runs around knee
Surrounds patellofemoral joint
Passes behind femoral condyles and tibial plateau

32

What lines the capsule?

Synovial membrane

33

What is the extent of the synovial membrane at the knee?

Doesn't line everything
Passes to sides of posterior cruciate ligament then passes around and in front of anterior cruciate ligament

34

What is the relationship of the cruciate ligaments with the capsule and the synovial membrane?

Intracapsular by extrasynovial

35

How do you tell the medial and lateral menisci apart?

Medial meniscus more open, with horns further apart
Lateral meniscus more circular, with horns closer together

36

Why is the anterior cruciate ligament associated with considerable bleeding when it tears, when it is relatively avascular?

Because of intimate association with synovial membrane
Blood mostly coming from tears to membrane

37

What is haemarthrosis?

Bleeding because of tear in synovial membrane

38

What is effusion?

Production of extra synovial fluid

39

What is the relationship between the capsule and the medial collateral ligament?

Medial collateral ligament essentially merges with medial aspect of capsule

40

What is the relationship between the capsule and the lateral collateral ligament?

Lateral collateral ligament somewhat detached from capsule

41

What reinforces the knee joint anteriorly?

Patellar tendon/ligament
Medial patellar retinaculum

42

From which muscles does the medial patellar retinaculum arise?

Vastus medialis
Vastus lateralis

43

What reinforces the knee joint laterally?

Popliteus
Biceps femoris
Iliotibial band

44

What reinforces the knee joint medially?

Pes anserius tendons
- Sartorius
- Gracilis
- Semitendinosus

45

What reinforces the knee joint posteriorly?

Oblique popliteal ligament

46

From what does the oblique popliteal ligament arise?

Semimembranosus

47

How does the lateral patellar retinaculum change the position of the patella?

Drags it laterally

48

Can the muscular reinforcements of the knee cover for damage to the cruciate ligaments?

Yes

49

What is the collective name for the muscular reinforcements of the knee?

Secondary restraints

50

How do you remember the muscle insertions of the pes anserinus from superior to inferior?

Say = sartorius
Grace = gracilis
Before = bursa
Tea = semitendinosus

51

What does the anterior cruciate ligament do?

Primary stabiliser in the A-P direction
Limits forward displacment of tibia on femur

52

When is the anterior cruciate ligament taut?

Extension
Full flexion

53

What is the loose packed position of the anterior cruciate ligament?

Semi-flexion

54

What are the two bands of fibres in the anterior cruciate ligament?

Anteromedial - most taut in extension
Posterolateral - most taut in complete flexion

55

What is the role of the anterior cruciate ligament when it tightens in the last 15-20 degrees of extension?

Axis for rotation during terminal extension

56

What does the anterior cruciate ligament allow during extension?

Medial rotation on fixed tibia
Limits backwards movement of lateral condyle

57

What can a person with a tear in their anterior cruciate ligament not do?

Properly lock joint > unstable in full extension

58

What sound is often heard with an injury to the anterior cruciate ligament?

Pop sound

59

When does injury to the anterior cruciate ligament occur?

Lateral rotation
Involves extension on weight-bearing leg

60

How much thicker is the posterior cruciate ligament than the anterior cruciate ligament?

2x

61

What is a common variant that reinforces the posterior cruciate ligament?

Meniscofemoral ligaments

62

What does the posterior cruciate ligament do?

Limits posterior displacement of tibia in knee flexion

63

When is the posterior cruciate ligament prone to injury?

Fall on flexed knee

64

What is the course of the popliteus muscle?

Runs across back of joint
Passes under lateral collateral ligament
Attaches to outside of lateral femoral condyle

65

What does the popliteus do?

Rotates femur laterally on fixed tibia

66

What is the role of the popliteus in unlocking the knee joint?

Contraction allows knee joint to flex to do other activities

67

Describe the superficial part of the collateral ligament?

Long, flat band

68

What is the relationship of the medial collateral ligament and the capsule and medial meniscus?

Deep part blends with capsule and attaches to medial meniscus

69

When is the medial collateral ligament taut?

Extension

70

When is the medial collateral ligament slack?

Flexion

71

What does the medial collateral ligament do?

Resist valgus forces and lateral rotation of tibia

72

What does the medial collateral ligament do when the anterior cruciate ligament is damaged?

Secondary restrain - limits anterior displacement of tibia

73

What is the unhappy triad?

Injury to all
- Anterior cruciate ligament
- Medial collateral ligament
- Medial meniscus

74

What separates the lateral collateral ligament from the lateral meniscus?

Popliteus tendon

75

What does the lateral collateral ligament do?

Resist varus forces

76

Which collateral ligament is more often injured?

Medial collateral ligament

77

What are the attachments of the lateral collateral ligament?

Lateral femoral condyle
Fibula

78

What is the shape of the menisci in the knee?

Wedge shaped

79

What are the functions of the menisci in the knee?

Shock absorb
Weight distribution
Separates joint into 2 cavities

80

With which structure do the menisci move in rotation?

Femur

81

By how much do the menisci increase area of contact?

1/3

82

Are the menisci within the synovial cavity or extrasynovial?

Within synovial cavity, but only bony attachments have covring

83

Which meniscus is more often injured, and why?

Medial meniscus, because
- Longer
- Horns further apart
- Less mobile

84

What kind of injuries can occur to the medial meniscus?

Nipped
Torn

85

What does an injury to the medial meniscus contribute to?

Locked knee

86

What happens if the menisci are completely removed?

Increased incidence of osteoarthritis

87

What are the two zones of the menisci, as defined by their blood supply?

Outer 1/3 has blood supply = red zone
Inner 2/3 avascular = white zone

88

What is a bursa?

Sac with small amount of fluid in it

89

What can happen to bursa with irritation?

Fluid inside can increase

90

Where is the quadriceps/suprapatellar bursa?

In knee joint, deep to quadriceps muscle

91

What is the largest bursa in the body?

Quadriceps bursa

92

What is the superior extent of the suprapatellar bursa?

Hand's breadth above tibiofemoral joint

93

Does the suprapatellar bursa communicate with the knee joint?

Yes

94

Where can an effusion at the knee joint expand into?

Suprapatellar bursa

95

How can the extent of the effusion into the suprapatellar bursa be estimated?

Pressing down on bursa to push fluid back into joint cavity

96

What is a baker's cyst?

Bursa deep to popliteus becomes fibrous

97

Where are there bursae in the knee?

Wherever
- Ligaments attach
- Large tendon sliding over bone

98

Where is the prepatellar bursa?

Superficial to patella

99

Where are the superficial and deep infrapatellar bursae?

Inferior to patella

100

Which bursae are non-communicating with the knee joint?

Prepatellar
Superficial infrapatellar
Deep infrapatellar

101

Can non-communicating bursae still become irritated?

Yes

102

What is the relationship between the synovial membrane and bursae at the knee joint?

Lines communicating bursae

103

What part of the cruciate ligaments does the synovial membrane conver?

Front

104

What are plicae?

Fringes/folds of synovial membrane

105

Where are there plicae in the knee joint?

Medially and laterally

106

What is the relationship between the synovial membrane and infrapatellar fat pad?

Synovial membrane sits on top of infrapatellar fat pad

107

Where is the patellofemoral joint?

In front of femur

108

What is the surface of the femur that articulates with the patella called?

Patellar surface

109

Where does the quadriceps tendon attach?

Upper aspect of patella

110

How does the patella move across the femur?

Slides up and down and rotates to some extent in grooved part of femur

111

What is the quadriceps' action on the patella?

Pulls patella up in extension
Pushes patella down in flexion

112

Where is the groove in which the patella moves across the femur?

Between lateral and medial femoral condyles

113

Which articular surface of the patella is larger: lateral or medial?

Lateral

114

What is a bipartite patella?

Two ossification centres of patella don't merge
Looks like fracture on x-ray

115

What structures maintain the normal alignment of the patellofemoral joint?

Vastus medialis
Medial patellar retinaculum
Raised lip on lateral femoral condyle

116

In which direction does the patella rotate during extension?

Medially

117

What happens if the raised lip of the lateral femoral condyle is diminished in size/absent?

Tendency for patella to slide laterally

118

In which direction do the fibres of vastus medialis approach the patella?

Come towards medial aspect
Move almost horizontally - that's why this section of muscle sometimes called vastus medialis oblique

119

What does the vastus medialis do in relation to the patella?

Helps keep it in place when moving from flexion to extension

120

What is the medial patellar retinaculum an extension of?

Vastus medialis to medial aspect of patella

121

Why is the medial patellar retinaculum a static structure?

Ligamentous

122

What acts upon the medial patellar retinaculum?

Vastus medialis

123

What happens if there is a deficiency in any of the structures that maintain the normal alignment of the patella?

Tendency for patella to slide in direction of femur

124

What is the angulation between the femur and tibia called?

Quadriceps (Q) angle

125

What tends to pull the patella laterally?

Quadriceps

126

What does abnormal tracking of the patella in its groove predispose you to?

Sublaxation
Dislocation

127

What is sublaxation?

Bone partially sliding across, but not completely dislocating

128

What part of the patella articulates with the femur if there is a mechanical problem of tracking of the patella in the femoral groove?

Medial part

129

Why doesn't the medial part of the patella like to articulate?

Cartilage not very thick > wears away

130

What can a mechanical problem of tracking of the patella in the femoral groove cause?

Cartilage on medial aspect of patella wears away > contributes to arthritic changes at patellofemoral joint > chondromalacia patella

131

What is chondromalacia patella?

Softening/degeneration of cartilage at patellofemoral joint