The Structure of The Knee Joint (week 6)

Question 1

state 3 basic structural facts about the knee joint

Answer 1

1. the largest, and one of the most complex, joints
2. a bicondylar (modified) hinge joint allowing flexion, extension, and some rotation
3. knee structure permits tremendous weight bearing capabilities as well as the mobility required for locomotor activities

Question 2

state the names of the 3 articulations found at the knee joint

Answer 2

1. medial tibiofemoral joint
2. lateral tibiofemoral joint
3. patellofemoral joint

Question 3

state 3 facts about the medial, and lateral, tibiofemoral joints

Answer 3

1. bicondylar articulation between the medial and lateral condyles of the tibia with the femur
2. permits a large ROM (flexion + extension)
3. permits a small degree of rotation (when the knee is flexed and the foot is off the ground)

Question 4

what is the patellofemoral joint

Answer 4

consists of articulation between the triangular shaped patella, encased in the patella tendon with the trochlear groove between the femoral condyles

Question 5

state 3 facts about the patella

Answer 5

1. a sesamoid bone which can improve the mechanical advantage of the knee by up to 50%
2. moves along the trochlear groove between the femoral condyles
3. posterior surface is covered with articular cartilage to reduce friction

Question 6

state 3 basic facts about the stability of the knee joint

Answer 6

1. shape of articulating bones provide little stability at the knee joint
2. tibial plateaus form only slight depressions separated by the intercondylar eminence
3. therefore, other structures are required to provide stability

Question 7

state what it is meant by the key term - tibial plateaus

Answer 7

tibial plateaus are where the condyles of the tibia form slight depressions separated by a region known as the ‘intercondylar eminence’

Question 8

state what it is meant by the key term - menisci

Answer 8

menisci are fibrocartilage semi lunar discs located between the tibial and femoral condyles are are connected by a transverse ligament

Question 9

state 2 structural facts about the menisci

Answer 9

1. thickest part at the peripheral borders and then taper down at the inner edges
2. the medial menisci merges with the joint capsule and the medial collateral ligament

Question 10

state 2 functional properties of the menisci

Answer 10

1. increase the connectivity of the tibial plateaus

2. distribute load in the knee over a large surface area and play a key role in shock absorption

Question 11

state 4 facts (3 functional) about the ligaments of the knee

Answer 11

1. cruciate ligaments make a cross with the knee capsule
2. limit anterior and posterior movement of the tibia in relation to the femur during flexion and extension
3. limit hyperextension (along with the posterior knee capsule)
4. also restrict medial and lateral rotation

Question 12

state what it is meant by the key term - anterior cruciate ligament (ACL)

Answer 12

connects the anterior aspect of the intercondylar eminence of the tibia to the posterior medial surface of the lateral condyle of the femur

Question 13

state what it is meant by the key term - posterior cruciate ligament (PCL)

Answer 13

connects the posterior aspect of the intercondylar eminence of the tibia to the anterior surface of the lateral condyle of the femur

Question 14

state what it is meant by the key term - lateral collateral ligament (LCL)

Answer 14

connects the lateral epicondyle of the femur to the head of the fibula and resists varus motion (knees out) of the knee

Question 15

state what it is meant by the key term - medial collateral ligament (MCL)

Answer 15

connects the medial epicondyle of the femur to the medial tibia and resists valgus motion (knees in) of the knee

Question 16

state 2 facts about the iliotibial band

Answer 16

1. strong band of connective tissue (fascia) connecting the tensor fascia latae (TFL) to the lateral condyle of the femur, and the lateral tuberosity of the tibia
2. stabilises the knee in extension and partial flexion

Question 17

state what it is meant by the key term - bursa

Answer 17

bursa are synovial fluid filled sacs which provide a cushion between a bone and a tendon, and/or muscles at a joint

Question 18

state the names, and locations, of the 3 bursa within the knee

Answer 18

1. suprapatellar bursa - between the femur and the quadriceps, largest in the body
2. subopopliteal bursa - between the lateral condyle of the femur and the popliteal muscle
3. semimembranosus bursa - between the medial head of the gastrocnemius and the semimembranosus tendon

Question 19

state the names, and locations, of the 3 bursa that are associated with the knee, but are not within the knee itself

Answer 19

1. prepatellar bursa - between the skin and the anterior surface of the patella
2. superficial infra patellar bursa - between the skin and the patella tendon
3. deep infra patellar bursa - between the tibial tuberosity and the patella tendon

Question 20

state the names of the 3 active movement pairs of the knee

Answer 20

1. flexion and extension
2. internal and external rotation
3. patellofemoral joint action

Question 21

state 2 facts about flexion and extension at the knee

Answer 21

1. popliteus ‘unlocks’ the knee at the beginning of flexion

2. hyperextension is limited by the shape of the bones, cruciate ligaments, and the posterior joint capsule

Question 22

state 2 facts about internal and external rotation at the knee

Answer 22

1. can occur passively due to external loads when the limb is weight bearing
2. can be generated by muscles when the knee is in a flexed position

Question 23

state 2 facts about patellofemoral knee joint action (active)

Answer 23

1. patella glides inferiorly and superiorly on the femur with the excursion of approx. 7 cm
2. patella tracking depends on the net force generated by the quadriceps and can be associated with knee pain

Question 24

state the names of the two passive movements at the knee

Answer 24

1. varus - knees out

2. valgus - knees in

Question 25

state what causes varus and valgus knee action

Answer 25

passive, generated by external loads being placed on the knee rather than by an active muscle force

Question 26

state the names of the 4 anterior knee muscles

Answer 26

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

Question 27

state the names of the 6 posterior knee muscles

Answer 27

1. semi membranosus
2. semi tendinous
3. bicep femoris
4. popliteus
5. gastrocnemius
6. plantaris

Question 28

what is the location of the - supra-patella bursa

Answer 28

between the femur and the quadriceps, it is the largest bursa in the body

Question 29

what is the location of the - subopopliteal bursa

Answer 29

between the lateral condyle of the femur and the popliteal muscle

Question 30

what is the location of the - semi-membranosus bursa

Answer 30

between the medial head of the gastrocnemius and the semi-membranosus tendon

Question 31

what is the location of the - pre-patellar bursa

Answer 31

between the skin and the anterior surface off the patella

Question 32

what is the location of the - superficial infra-patellar bursa

Answer 32

between the skin and the patellar tendon

Question 33

what is the location of the - deep infra-patellar bursa

Answer 33

between the tibial tuberosity and the patellar tendon

Question 34

what type of joint is the patellofemoral joint ?

Answer 34

Saddle joint

Question 35

state what it is meant by the key term - ‘unhappy triad’

Answer 35

the ‘unhappy triad’ refers to a combined injury to the anterior cruciate ligament, medial collateral ligament and the medial meniscus

Question 36

state the names of the other 3 contributing ligaments to knee stability

Answer 36

1. oblique popliteal ligament
2. arcuate popliteal ligament
3. transverse ligament