2. The knee joint Flashcards Preview

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Flashcards in 2. The knee joint Deck (24)
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1
Q

name the 2 articulations of the knee joint

A
  1. tibiofemoral: medial and lateral femoral condyles articulating with tibia
  2. patellofemoral: distal anterior femur with patella
2
Q

what is the function of the patella

A

patella is formed inside quadriceps femoris tendon:
1- allows quadriceps femoris (main knee extensor) to be inserted directly over knee, increasing its efficiency
2- minimises wear and tear of tendon

3
Q

which structures are found between the femur and tibia articulating surfaces

A

lateral and medial menisci (fibrocartilaginous)

4
Q

what is the function of the knee menisci

A

1- deepen articular surface of tibia… increase joint stability
2- shock absorbers

5
Q

how are the lateral and medial menisci attached

A
  1. Are attached at both ends to the intercondylar area of tibia.
  2. Anterior edges of menisci joined by transverse ligament of knee.
  3. Medial meniscus fixed to tibial (medial) collateral ligament and joint capsule (whilst lateral meniscus is smaller and has no extra attachments).
6
Q

how can damage to the medial meniscus occur

A

tearing of medial collateral ligament

7
Q

which ligament stabilises the patella and where does it attach

A

patellar ligament: continuation of quadriceps femoris tendon distal to patella and attaching to tibial tuberosity

8
Q

which ligaments prevent lateral/medial mov. at the knee and where do these attach

A
  1. medial (tibial) collateral ligament - wide and flat, runs from medial epicondyle of femur to medial surface of tibia (also attaching to medial meniscus)
  2. lateral (fibular) collateral ligament - thinner and rounder, runs from lateral epicondyle of femur to depression on lateral surface of fibular head
9
Q

which ligaments prevent anterior and posterior dislocation of femur on tibia and where do these attach

A
  1. anterior cruciate ligament: runs from anterior intercondylar region of tibia and ascends posteriorly to attach to intercondylar fossa of femur - prevents anterior dislocation of tibia to femur
  2. posterior cruciate ligament: runs from posterior intercondylar region of tibia and ascends anteriorly to attach to intercondylar fossa of femur - prevents posterior dislocation of tibia to femur
10
Q

name the 4 bursae found at the knee joint and their location

A
  1. prepatella bursa - between apex of patella and skin
  2. suprapatella bursa - between quadriceps femoris tendon and femur
  3. infrapatella bursa - between patella ligament and skin (superficial) and between patella ligament and tibia (deep)
  4. semimembranosus bursa - posterior to knee joint, between semimembranosus and medial head of gastrocnemius
11
Q

what are Housemaid’s knee and Clergyman’s knee

A

Housemaid’s knee = prepatella bursitis

Clergyman’s knee = infrapatella bursitis

12
Q

name 5 extracapsular ligaments that strengthen the knee joint capsule

A
  1. patellar
  2. tibial collateral
  3. fibular collateral
  4. oblique popliteal
  5. arcuate popliteal
13
Q

why is there relatively poor stability at the knee

A

curved femoral condyles lying on flat femoral head

14
Q

which structures limit knee joint flexion

A
  1. tension of rectus femoris (esp. with hip joint extended)
  2. tension of vastus medialis, lateralis and intermedius
  3. soft tissue apposition posteriorly
15
Q

which structures limit knee joint extension

A
  1. ligaments: ACL, PCL, lateral and medial collaterals and oblique popliteal
  2. posterior joint capsule
16
Q

which structures limit knee joint internal rotation

A

ACL and PCL

17
Q

which structures limit knee joint external rotation

A

lateral and medial collaterals

18
Q

which muscles mediate knee flexion

A
  • hamstrings
  • popliteus
  • gracilis and sartorius
19
Q

which muscles mediate knee extension

A

quadriceps femoris

20
Q

which muscles mediate knee lateral rotation

A

biceps femoris

21
Q

which muscles mediate knee medial rotation

A
  • semimemranosus and semitendinosus

- gracilis and sartorius

22
Q

how does the knee ‘lock’

A

passive medial rotation of femur on tibia

23
Q

how does the knee ‘unlock’

A

lateral rotation of femur on tibia due to popliteus contracting

24
Q

why does the knee lock

A
  • more adapted for weight bearing: required for standing and walking (loading response)
  • thigh and leg muscles can relax briefly without making knee joint too unstable