Anatomy of the knee Flashcards Preview

Module 204 Theme 2 > Anatomy of the knee > Flashcards

Flashcards in Anatomy of the knee Deck (59):
1

Where is the knee joint?

Articulation between distal femur and proximal tibia
Articulation between femur and patella

2

What type of joint is the knee?

Synovial bicondylar hinge joint

3

List the functions of the knee

Unusual

Weight–bearing

Mobility
- Extension/flexion
- Some rotation when flexed

4

List the bony structures which strengthen the knee

- Bony expansions
- Locking mechanism
- Femoral angle

5

List the soft tissue structures which strengthen the knee

- Ligaments
- Menisci
- Muscles

6

List the bony expansions of the knee

Epicondyles
Femoral condyles
Tibial condyles
Intercondylar fossa

7

What is the function of the bony expansions?

Provides a strong base

8

What is the function of the locking mechanism

Reduces amount of energy required when extended

9

Describe the shape of the femoral surfaces in flexion

round

10

Describe the shape of the femoral surfaces in extension

Flat

11

What constitutes the locking mechanism

Shape of the femur
Rotation
Centre of gravity

12

What does medial rotation of the femur on the tibia in extension do?

Tightens the ligaments of the knee

13

Where is the centre of gravity in the knee?

In front of the knee

14

What is the function of the centre of gravity in the knee?

Maintains extension

15

Describe the femoral angle

Adducted femur brings knee joint under pelvis

Critical for weight bearing

Occurs during development

16

What is normal joint alignment in the knee?

Vertical line through centre of femoral head,
Centre of knee and centre of ankle

17

Describe varus deformity (Genu varum)

Deformity in the angle tween the femur and tibia
Medial displacement of the tibia - common in children under 2 and rickets
Pushes the knees apart - bow legged - decrease in Q angle

18

Describe valgus deformity (Genu valgum)

Lateral displacement of the tibia
- Common in children aged 2-4, rickets, arthritis
Brings knees together - ‘Knock-kneed'
Increases Q angle

19

What is the function of the ligaments in the knee?

Provide stability

20

Name the two groups of ligaments in the knee

Intracapsular
Extracapsular

21

Where are the Extracapsular ligaments found?

Outside of the capsule

22

Where are the Intracapsular ligaments found?

Inside the capsule

23

Name the Extracapsular ligaments

- Medial collateral
- Lateral collateral

24

Name the Intracapsular ligaments

- Anterior cruciate
- Posterior cruciate

25

Describe the lateral/fibular collateral ligament

Strong round cord
Prevents medial displacement of the tibia

26

What is a varus deformity?

Tear of the LCL

27

Describe the medial/tibial collateral ligament

Broad flat band
- Reinforces joint capsule
- Prevents lateral displacement of tibia

28

What is a valgus deformity?

Tear of the MCL

29

Where is the anterior cruciate ligament?

anterior in relation to the tibia

30

Where is the posterior cruciate ligament?

Posterior in relation to the tibia

31

What is the function of the anterior cruciate ligament

Prevents anterior displacement of tibia on femur

32

What is the function of the posterior cruciate ligament?

Prevents posterior displacement of tibia on femur
Stabilizer when knee is flexed

33

What is the function of both cruciate ligaments?

Maintain femur against tibia

34

Which is the weaker cruciate ligament?

Anterior cruciate

35

Describe injury to the anterior cruciate ligament

- Common sports injury
- Caused by sharp twisting of knee
- Immediate decreased range of movement

36

Describe the lachman test

- Patient in supine position with knee bent 20-300 of flexion

- Move tibia anteriorly and posteriorly while maintaining position of femur

- Laxity during this manoeuvre indicates anterior cruciate ligament injury

37

What are the menisci of the joints

Crescent-shaped plates of fibrocartilage
- Deepen the articulating surfaces/stability
- Shock absorbers
- Provides smooth viscous film for joint

38

Describe the menisci attachments

Horns of menisci attached to intercondylar area of tibia
Mobile - Accommodates rolling of femoral condyles
Medial meniscus less mobile- Attached to medial collateral ligament

39

What can be commonly ruptured in the knee?

- Anterior cruciate ligament
- Medial collateral ligament
- Medial meniscus (attached to MCL)

40

Describe the iliotibial tract

- Reinforces joint capsule

- Stabilizes extended knee
(gluteus maximus, tensor fascia lata)

41

List the 4 heads of the quadriceps

Rectus femoris
Vastus lateralis
Vastus intermedialis
Vastus medialis

42

What is the function of the quadriceps

major stabilizing muscle of the knee
Extends the leg

43

Describe the patellar

- Protects quadriceps tendon from stresses during locomotion
- Smooth oval facet of posterior surface for articulation with femur

44

How can the patella be fractured?

due to fall or blow to the knee

45

How can the patella be dislocated?

sudden twisting/jumping or ligamentous laxity

46

Name the 3 hamstring muscles

- Biceps femoris
- Semimembranosus
- Semitendinosus

47

What is the function of the hamstring muscles

- Also medially and laterally rotates leg when knee flexed
- And extends thigh

48

Which 2 muscles flex the leg?

Hamstrings and gastrocnemius

49

Describe how the extended leg can be unlocked

Popliteus unlocks knee joint
- Laterally rotates femur on tibia when foot is on ground

50

Describe the synovial membrane

From margins of articular surfaces of femur to tibia
Attached to patella
Extends superiorly behind quadriceps tendon
Cuffs anterior surface of cruciate ligaments

51

What is the function of the infrapatellar fat pad?

separates synovial membrane from patellar ligament

52

What is the function of bursae?

- Protection

- Reduce friction

53

What are bursae?

Synovial fluid filled sac lined by synovial membrane

54

What is bursitis?

Inflammation of bursae
Due to repetitive movements or direct pressure

55

Describe Prepatellar bursitis

Seen in carpet fitters
Leaning forward on the knees brings the prepatellar bursa in contact with floor

56

Describe Infrapatellar bursitis

- After prolonged periods of prayer clergymen sat back on their heels bringing infrapatellar bursa in contact with floor

57

Describe Bakers (popliteal cyst)

Abnormal fluid filled sacs in popliteal fossa
- Due to herniation of synovial membrane/bursa
Common in patients with chronic
inflammatory joint disease (e.g. arthritis)
- Presents as swelling in the popliteal fossa
- Can affect joint movement

58

How do you treat bakers cyst?

aspiration and cortisone injection

59

Describe the vascular supply to the knee

Anastomosis - femoral artery and popliteal artery