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ANAT 101 > Topic 4 > Flashcards

Topic 4 Flashcards

1
Q

identify, classify and state the functions of the patella

A 
Sesamoid bone
Base, apex, articular facets
Centred in intercondylar
groove of femur
Mechanical advantage for
knee extension
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2
Q

describe the joint capsule of the knee

A 
No complete capsule
Deficient anteriorly on femur
where quadriceps tendon is
Deficient anteriorly on tibia
where patella ligament attaches
to tibial tuberosity
Deficient posteriorly where
tendon of popliteus emerges
(posterior to lateral tibial condyle)
Receives much additional
ligamentous reinforcement
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3
Q

describe the synovial membrane in the knee joint

A 
Lines the joint capsule
Extensive and complex
Anteriorly attaches to patella
Posteriorly closes off
intercondylar fossa
Does not enclose the ACL or
PCL
Communicates with some
bursa
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4
Q

what is knee retinacula

A 
Medial & lateral patellar retinaculum
Aponeurosis – flat tendon
From vastus medialis & vastus lateralis
Medial retinaculum blends with
periosteum of tibia
Medial patellofemoral ligament
Adductor tubercle to vastus medialis
onto superomedial patella
Lateral retinaculum blends with iliotibial
tract
Some cross-over of fibres to over side

coming off the vastus lateralis and vastus medialis are the lateral and medial patella retinaculum - which are broad sheets connective tissue that sweep over the gap of the joint capsule. they compensate for the gap in the joint capsule.

the medial retinaculum blends with the periosteum of the tibia. We have an extra ligament called the patelloligament which prevents a lateral displacement of the patella.

lateral retinaculum blends with the iliotibial tract.

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5
Q

list the bursae in the knee joint

A 
Pes anserine
Suprapatellar
Extends 6cm superior to patella!
Infrapatellar
prepatella
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6
Q

describe the fibular/lateral collateral

A

Fibular/Lateral collateral
ligament - extracapsular

Attaches:
Lateral femoral epicondyle
Lateral surface head of fibula

Limits:
Extension
Lateral rotation
Adduction or VARUS forces

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7
Q

describe the popliteofibular ligament

A

Popliteofibular ligament - extracapsular

Attaches:
Popliteus tendon
Apex of head of fibula

Limits:
Lateral rotation of the tibia

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8
Q

describe the patella ligament

A

Patella ligament - capsular

From patella to tibial tuberosity
Continuation of quadriceps
tendon
Receives the patellar retinacula

Function:
Mechanical advantage in knee
extension

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9
Q

describe the tibial medial collateral ligament

A

Tibial/Medial collateral ligament - capsular

Attaches:
Medial femoral epicondyle
Medial tibial condyle
Medial tibial shaft
Medial meniscus

Limits:
Extension
Medial rotation
Abduction or VALGUS forces

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10
Q

describe the oblique popliteal ligament

A 
Oblique Popliteal - capsular 
Strengthens central posterior
joint capsule
Is an expansion of the tendon
of semimembranosus
Travels superolaterally to
femur
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11
Q

describe the arcuate popliteal ligament

A 
Arcuate Popliteal - capsular 
Strengthens inferolateral
posterior joint capsule
Is an expansion of the
tendon of biceps femoris
attachment
Travels superomedially
over popliteus
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12
Q

describe the anterolateral ligament

A 
Anterolateral ligament - capsular 
Attaches
lateral femoral condyle
midway between
anterolateral tubercle
(Gerdy’s tubercle) & head
of fibula
Some sources consider it
part of the ITB
stabiliser for rotation of the
tibia?
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13
Q

describe the ACL

A 
ACL - intracapsular 
Attaches
anterior intercondylar area of
tibia
posteromedial surface of lateral
femoral condyle
Extra-synovial
Limits
medial rotation
anterior slide of tibia on femur
3 anteriors on this slide
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14
Q

describe the PCL

A 
PCL - capsular 
Attaches
posterior intercondylar area of
tibia
lateral surface of medial femoral
condyle
attaches to lateral meniscus
Extra-synovial
Limits
medial rotation
posterior slide of tibia on femur
3 posteriors on this slide
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15
Q

describe the posterior meniscofemoral ligament

A 
Posterior meniscofemoral - capsular 
Connects lateral meniscus to
PCL
Secondary restraint to support
PCL
More in functional knee lecture
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16
Q

describe the lateral and medial meniscus

A

Crescent shaped wedges of
fibrocartilage, thicker at ‘edges’

Shock absorption
Increase congruence
Medial meniscus - Larger, C-shaped, less
mobile as more attachments
Lateral meniscus - Smaller, almost circular

17
Q

describe the tibiofemoral joint

A

Tibiofemoral
Synovial
Condyloid (modified hinge)
Biaxial

Movements:
Flexion 140º
Extension 0º (hyperextension)
Internal/medial rotation 10º-20º if flexed
External/lateral rotation 30º-40º if flexed

18
Q

describe the patellofemoral joint

A 
Patellofemoral
Patella surface of femur
Articular surface of patella
(facets)
Synovial
Plane
19
Q

when is the knee in close packed position

A

full extension

20
Q

factors contributing to stability at the hip

A
  1. articular fit - reasonable congruency
  2. acetabulum labrum - deepens socket and increases congruency
  3. strong capsule - reinforced by ligaments
  4. angle of inclination - increases contact area
  5. muscles being parallel to neck of femur.
21
Q

what are factors contributing to mobility at the hip joint

A
  1. acetabulum labrum - provides increased surface area for femoral head.
  2. ball and socket joint - multiaxial
22
Q

how does the knee unlock?

A

Popliteus “unlocks”
knee by medially
rotating tibia.

23
Q

what is the functional significance the locking mechanism of the knee joint?

A 
1. Important contributor to
tibiofemoral joint stability in
extension
2. “Close packed position”
• No muscle effort required to maintain
full knee extension
• Stable joint position: Maximum
contact between joint surfaces, tibial
tubercles lodged in the intercondylar
notch, ligaments tense
• BUT also uncomfortable, not the
preferred resting position of the joint
24
Q

what are the factors contributing to stability at the knee?

A
  1. STATIC: combination of non contractile and
    bony elements
    e.g. menisci, ligaments, capsule, articular cartilage,
    ITB
  2. DYNAMIC: muscles acting on or across the
    knee joint
    e.g. quadriceps, hamstrings, sartorius, TFL, gracilis,
    gastrocnemius, popliteus, ITB
25
Q

describe the menisci as a factor contributing to the stability

A

Static: Menisci
• Due to their complex anatomy, the menisci serve a variety of
biomechanical functions such as:
1. withstand load bearing forces
2. increase contact area at the tibiofemoral joint  reduces stress at
the joint surfaces
3. assist in movement of femoral condyles
4. assist in stabilising translatory movements
• Menisci occupy ~ 60% of contact area between femoral condyles and
tibial plateau
• Menisci transmit >50% total axial load applied to tibiofemoral joint.

26
Q

what are the attachments of the medial and lateral menisci

A 
attachments of medial
meniscus:
• medial collateral lig
• anterior and
posterior cruciate ligs
• semimembranosus
attachments
of lateral meniscus:
• posterior cruciate lig
• medial femoral
condyle via
meniscofemoral ligs
• popliteus

medial meniscus has greater ligamentous and capsular
restraint  limited motion, contributor to greater
incidence of injury?

27
Q

what are the movements of the menisci

A

Movements of the menisci:

  • considerable distortion throughout range
  • both move posteriorly during flexion (lateral > medial)
  • keeps the menisci under the femoral condyles
  • both active and passive elements contribute to movt.
28
Q

describe the ligaments as a factor contributing to stability at the knee joint

A

Static: Ligaments
• combinations of structures provide stability at the knee –
no single structure in isolation
• concept of primary and secondary restraints
work together to provide stability
primary restraints – ‘workers’
secondary restraints – ‘helpers’
• if primary restraint is damaged, the secondary restraint
takes the load  deterioration and increased joint
instability

29
Q

describe the iliotibial band as a factor contributing to stability

A

Dynamic: Iliotibial band (ITB)
• part of the more extensive fascia lata
• from the fascia surrounding tensor fascia lata and
gluteus maximus and medius
• extends to the anterolateral tibia
• crosses both hip and knee
• has fibrous connections to biceps femoris, vastus
lateralis and the lateral patellar retinaculum – may
influence patella tracking through these connections

• consistently taut regardless of hip or
knee position
• falls in front of the axis of the knee in
extension, slips behind the axis in
flexion (and is more prominent in knee
flexion)
• affords some lateral joint stability
particularly in flexion
• assists ACL in preventing anterior slide
of tibia on femur
30
Q

describe the quadrate femoris as a factor contributing the stability of the knee joint

A 
major extensor of knee
• all parts of quadriceps
femoris work throughout the
range of knee extension
 stabilises the patella
within trochlear
groove
• greatest force needs to be
developed at the end of
extension range – final
15degs greatest mechanical
disadvantage
31
Q

what are the functions of the vastus medialis oblique and longitudinal

A

Vastus medialis - longitudinal fibres (strongly
bound to VI proximally):
• knee extensor

Vastus medialis - oblique fibres:

• weak knee extensor
• prominent activation in last 40º of knee
extension
• medial patella stabiliser - prevents vastus
lateralis from laterally dislocating the patella
• increases the efficiency of vastus lateralis in
knee extension by realigning pull (required
force decreased by 13%) (Mirzabeigi et al,
1999)

32
Q

what is the primary and secondary restraint for anterior tibial displacements

A

primary - ACL

secondary - medial collateral lig and iliotibial band

33
Q

what is the primary and secondary restraint for posterior tibial displacement

A

primary - PCL

secondary - medial collateral, lateral collateral and oblique popliteal

34
Q

what is the primary and secondary restraint for posterior tibial displacement

A

primary - PCL

secondary - medial collateral, lateral collateral and oblique popliteal

35
Q

what is the primary and secondary restraint for abduction (valgus) at the knee

A

primary - medial collateral

secondary - ACL, PCL, oblique popliteal lig

36
Q

what is the primary and secondary restraint for adduction (varus) at the knee

A

primary - not ligamentous

secondary - lateral collateral, posterolateral corner

37
Q

what is the primary and secondary restraint for internal tibial rotation

A

primary - medial collateral and posteromedial corner

secondary - ACL and PCL

38
Q

what is the primary and secondary restraint for external tibial rotation

A

posterolateral corner complex - which includes the lateral collateral and popliteal fibular ligament

ANAT 101 (12 decks)

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