Knee

Question 1

Articulation of the knee joint is between:

Answer 1

1. femoral condyles and the tibial condyles
2. patella and femur

Question 2

Label:

Answer 2

Question 3

Label:

Answer 3

Question 4

Label:

Answer 4

Question 5

Where do the minisci of the knee sit?

Answer 5

tibial condyles

Question 6

Menisci divide the joint cavity into two compartments:

Answer 6

• suprameniscal: between the femoral condyles and the menisci
• inframeniscal: between the menisci and the tibial condyles

Question 7

Extracapsular ligament support of the knee joint:

Answer 7

EX-OPALM

1. Oblique Popliteal
2. Patellar Ligament
3. Arcuate Popliteal
4. Lateral Collateral
5. Medial Collateral

Question 8

Patellar Ligament & Retinacula:

Answer 8

• Anterior support of the knee joint.
• patella retinaculum come off both sides of the patellar ligament to further reinforce

Question 9

Lateral Collateral Ligament:

Answer 9

• provides lateral support to knee joint
• resists VARUS stress (when distal bones go medial)
• Lateral Femoral Epicondyle to Apex of Fibula

Question 10

Medial collateral ligament:

Answer 10

• provides medial support to knee joint
• resists VALGUS stress (when distal bones go lateral)
• Medial Femoral Epicondyle to Tibia and Medial Meniscus

Question 11

Which collateral ligament of the knee is attached to a miniscus?

Answer 11

• medial collateral ligament
• attached to medial miniscus

HIGH PROBABILITY OF MEDIAL MENISCUS TEAR WITH A MCL TEAR

Question 12

Popliteal ligaments:

Answer 12

• oblique and arcuate popliteal
  
  • arcuate arches of popliteus muscle on lateral side of knee joint
• resist hyperextension of knee joint

Question 13

What ligament resists varus stress of the knee?

Answer 13

• lateral collateral ligament

Question 14

What ligament resists valgus stress of the knee?

Answer 14

• medial collateral ligament

Question 15

What ligament resist hyperextension of the knee?

Answer 15

• arcuate and oblique popliteal

Question 16

Intraarticular ligaments of knee joint:

Answer 16

IN-PALM

• Posterior Cruciate
• Anterior Cruciate
• Lateral Meniscus
• Medial Meniscus

Question 17

Label:

Answer 17

• medial miniscus is larger

Question 18

Why must interior meniscus tears be removed rather than sutured?

Answer 18

• interior of mensicus is avascular - would not heal.
• Outer third of meniscus is vascular and can be sutured in repair

Question 19

Anterior cruciate ligament origin and insertion:

Answer 19

APEX

• begins in the anterior intercondylar area of the tibia and runs Posteriorly, inserting into the EXternal (lateral) condyle of the femur.

Question 20

Posterior cruciate ligament origin and insertion:

Answer 20

PAIN

• begins in the posterior intercondylar area of the tibia and runs Anteriorly, inserting into the INternal (medial) condyle of the femur.

Question 21

Posterior collateral ligament (PCL) function:

Answer 21

• Taut during Flexion
• Resists Posterior Displacement of Tibia on the Femur
• Resists anterior displacement of femur on tibia

Question 22

Anterior collateral ligament (ACL) function:

Answer 22

• Taut during Extension
• Resists Anterior Displacement of Tibia on the Femur
• Resists posterior displacement of femur on tibia

Question 23

Label:

Answer 23

• red = PCL
• blue = ACL

Question 24

Steps in knee extension when the tibia is fixed and the femur moves:

Answer 24

1. Quad contraction begins anterior rolling of femur on tibia in suprameniscal compartment. Checked by PCL.
2. Simultaneous posterior translation (sliding) of femur on tibia in inframeniscal compartment to prevent femur from rolling off tibial surface. Checked by the ACL.
3. Near full extension, medial rotation of femur on tibia and locking of knee in full extension.

Question 25

Anterior rolling in knee extension when the tibia is fixed and the femur moves occurs in what compartment?

Answer 25

* suprameniscal compartment. * checked by PCL.

Question 26

Posterior rolling in knee extension when the tibia is fixed and the femur moves occurs in what compartment?

Answer 26

* inframeniscal compartment. * checked by ACL.

Question 27

Why does medial rotation of femur on tibia occur in knee extension when the tibia is fixed?

Answer 27

* lateral femoral condyle reaches limit of its articular surface and stops rolling while the longer articular surface of the medial femoral condyle continues to roll in the suprameniscal compartment. ## Footnote **MEDIAL FEMORAL CONDYLE HAS MORE SURFACE AREA AND CONTINUES ANTERIOR ROLLING**

Question 28

What muscle unlocks the knee joint following extension?

Answer 28

* popliteus muscle * only function of this muscle

Question 29

How does the popliteal muscle unlock the knee joint?

Answer 29

* Pulls the lateral epicondyle of the femur backwards - laterally rotating the femur on the fixed tibia to unlock the knee joint.

Question 30

Unhappy triad:

Answer 30

* Tears of: * Medial Collateral Ligament (due to valgus stress) * Medial Meniscus (due to valgus stress) * ACL (due to twisting/hyperextension)

Question 31

Applied valgus stress tests the:

Answer 31

MCL.

Question 32

Applied varus stress tests the:

Answer 32

LCL.

Question 33

Tests to test the ACL and PCL:

Answer 33

* Lachan test and drawer test * pull forward to test ACL * push backward to test PCL