6.6 Knee

Question 1

What are the main joints of the knee?

Answer 1

Tibiofemoral joint, patellofemoral joint, and sometimes the proximal tibiofibular joint.

Question 2

What type of bone is the patella?

Answer 2

A sesamoid bone within the quadriceps tendon.

Question 3

What is the function of the menisci?

Answer 3

Increase contact area, reduce compressive forces, and stabilize the joint.

Question 4

Which portion of the meniscus has better blood supply?

Answer 4

The outer one-third (red zone).

Question 5

Which portion of the meniscus is avascular?

Answer 5

The inner two-thirds.

Question 6

What do the ACL and PCL resist?

Answer 6

Extremes of knee motion and anterior-posterior shear forces.

Question 7

How are the cruciate ligaments named?

Answer 7

By their attachment on the tibia.

Question 8

What is the direction of the ACL fibers?

Answer 8

They run obliquely in a posterior, superior, and lateral direction.

Question 9

What is the role of the cruciate ligaments in proprioception?

Answer 9

They contain mechanoreceptors that help detect knee position and movement.

Question 10

What are the arthrokinematics of tibia-on-femur extension?

Answer 10

Roll and slide occur in the same (anterior) direction.

Question 11

What are the arthrokinematics of femur-on-tibia extension?

Answer 11

Roll is anterior, slide is posterior.

Question 12

What is the screw-home mechanism?

Answer 12

The automatic rotation that locks the knee in full extension for stability.

Question 13

What happens during the screw-home mechanism in open-chain extension?

Answer 13

The tibia externally rotates on the femur.

Question 14

What happens during the screw-home mechanism in closed-chain extension?

Answer 14

The femur internally rotates on the tibia.

Question 15

Why does the screw-home mechanism occur?

Answer 15

Because the medial femoral condyle is longer and ligaments tighten near full extension.

Question 16

Is the screw-home mechanism under active control?

Answer 16

No, it happens passively due to joint congruency and ligament tension.

Question 17

What direction does the patella move during knee extension?

Answer 17

Superiorly along the femur.

Question 18

What determines stress on the patellofemoral joint?

Answer 18

The varying contact area between the patella and femur at different angles of knee flexion.

Question 19

Which bone of the knee is non-weight-bearing but serves as a muscle attachment site?

Answer 19

Fibula.

Question 20

What is the largest sesamoid bone in the body?

Answer 20

Patella.

Question 21

Where does the patellar tendon insert?

Answer 21

On the tibial tuberosity.

Question 22

What covers the posterior aspect of the patella?

Answer 22

Articular cartilage.

Question 23

What type of joint movement occurs when squatting?

Answer 23

Femur-on-tibia knee flexion.

Question 24

What type of joint movement occurs when sitting and extending the leg?

Answer 24

Tibia-on-femur knee extension.

Question 25

What type of rotation occurs when the tibia and toe move outward relative to the femur?

Answer 25

Tibial external rotation.

Question 26

What type of rotation occurs when the tibia and toe move inward relative to the femur?

Answer 26

Tibial internal rotation.

Question 27

What happens to the roll and slide in femoral-on-tibia flexion?

Answer 27

Roll is posterior, slide is anterior.

Question 28

What structure increases knee joint stability and contact area?

Answer 28

The menisci.

Question 29

What is the trochlear groove shape of the femur?

Answer 29

Concave side-to-side and convex front-to-back.

Question 30

Which muscle group attaches into the patella via the quadriceps tendon?

Answer 30

Quadriceps.