Exam 3 - Knee Anatomy

Question 1

Main points about the knee

Answer 1

1. Largest synovial joint in the body
2. separates the body’s two largest lever arms
3. compound joint - tibiofemoral joint - patellofemoral joint
4. patella largest sesamoid bone
5. patella acts as a pulley - gives mechanical advantage to quads

Question 2

What are the principle movements of the knee?

Answer 2

flexion
extension
rotation

Question 3

What is the “screw-home mechanism”?

Answer 3

during knee extension, the tibia externally rotates to increase stability

Question 4

What gives the tibiofemoral joint its stability?

Answer 4

• static restraints from the bones and ligaments

- dynamic restraints

Question 5

Describe the anatomy of the meniscus

Answer 5

1. semilunar cartilage
2. the MEDIAL meniscus is “C-shaped”
3. the LATERAL meniscus is “O-shaped”
4. overall wedge shaped

Question 6

What are the attachment points of the lateral meniscus?

Answer 6

• intercondylar area - attaches to PCL

- posterior - medial femoral condyle via meniscofemoral ligament

Question 7

How is the medial meniscus attached?

Answer 7

• anterior - anterior tibia

- posterior - posterior tibia

Question 8

What is the common mechanism of injury to the meniscus?

Answer 8

Loaded-twisting motion

Question 9

What are the primary symptoms of a meniscus injury?

Answer 9

• report that the knee “gave out”
• clicking or popping sound
• effusion
• deep squat/duck walk painful

Question 10

Between the medial and lateral meniscus, which is more commonly injured?

Answer 10

medial

Question 11

How does the meniscus receive its blood supply?

Answer 11

1. outer 1/3 from genicular artery

2. inner 2/3 is avascular, and receives nourishment from synovial fluid

Question 12

What 4 muscles are responsible for extension of the knee?

Answer 12

1. rectus femoris
2. vastus lateralis
3. vastus medialis
4. vastus intermedius

Question 13

What are the 3 primary muscles involved in knee flexion?

Answer 13

Hamstrings

1. biceps femoris
2. semitendonosis
3. semimembranosis

Question 14

What are the secondary muscles involved in knee flexion?

Answer 14

1. gastrocnemius
2. gracilis
3. sartorius

Question 15

What is the function of a bursa?

Answer 15

It’s a fluid-filled sac in high-friction areas that eases the friction of the muscles and tendons over body prominences

Question 16

What are the 3 bursa of the anterior knee?

Answer 16

1. suprapatellar bursa
2. prepatellar bursa
3. infrapatellar bursa

Question 17

What is a plica?

Answer 17

distinct permanent fold of the synovium of the knee

Question 18

What is the mechanism of injury for the plica?

Answer 18

• direct blow
• tear from a twist
• repeat stress
• weak vastus medialis & vmo
• hamstring tightness

Question 19

What is the infrapatellar fat pad?

Answer 19

• largest fat pad in knee
• serves as a cushion to the front of the knee
• separates the patellar ligament from the joint capsule
• can become enlarged if irritated

Question 20

What are the main ligaments in the knee?

Answer 20

LCL - lateral collateral ligament
MCL - Medial collateral ligament
ACL - Anterior cruciate ligament
PCL - Posterior cruciate ligament
Oblique popliteal ligament
Patellar ligament

Question 21

What is the function and attachment points of the LCL?

Answer 21

Provides lateral stability
Attachments:
- lateral condyle of the femur
- head of the fibula

Question 22

What are the attachments and function of the MCL?

Answer 22

Provides medial stability
Attachments:
- medial condyle of femur
- medial meniscus
- medial tibia

Question 23

What are the deep fibers of the MCL?

Answer 23

Menisco-femoral

Menisco-tibial

Question 24

What is the MOI of the MCL?

Answer 24

valgus force from the lateral side

Question 25

What is the function of the ACL?

Answer 25

prevents tibia from translating anteriorly on the femur

Question 26

What are the 2 major fiber bundles of the ACL?

Answer 26

Anteromedial | Posterolateral

Question 27

What are the attachments for the ACL?

Answer 27

Distal - anteromedial bundle at tibial intercondylar area - ascends posterolaterally twisting on itself Proximal - posteromedial aspect of the lateral femoral condyle

Question 28

What is the function of the PCL?

Answer 28

Key stabilizer for basic knee motion/function | - creates compressive forceacross the knee joint between the tibia and femur

Question 29

What are the attachments of the PCL?

Answer 29

distal - posterior tibial intercondylar area - ascends anteromedially proximal - lateral surface of the medial femoral condyle

Question 30

What is the function and attachments of the Oblique popliteal ligament?

Answer 30

Provides posterior stability Attachments: Distal - posterior medial aspect of tibia Proximal - posterior lateral aspect of femur

Question 31

Patellar ligament attachments

Answer 31

Distal - tibial tuberosity | Proximal - inferior pole of patella

Question 32

Bones of the knee

Answer 32

1. medial condyle of femur 2. medial condyle of femur 3. patella 4. medial & lateral joint lines 5. medial condyle of tibia 6. lateral condyle of tibia 7. tibial tuberosity 8. shaft of tibia 9. head of fibula 10. shaft of fibula

Question 33

muscles of the knee

Answer 33

1. vastus medialis 2. rectus femoris 3. vastus lateralis 4. biceps femoris 5. semitendinosus 6. semimembranosus 7. gastrocnemius 8. tibialis anterior

Question 34

Ligaments of the knee

Answer 34

1. medial collateral ligament 2. lateral collateral ligament 3. patellar ligament 4. oblique popliteal ligament