Knee Joint

Question 1

What type of joint is the knee joint? Describe it.

Answer 1

Hinge-type bicondylar synovial joint. Joints lined with hyaline cartilage and enclosed in single joint cavity.

Question 2

Name the three bones of the knee joint

Answer 2

Patella, femur, tibia

Question 3

Name the two articulations in the knee joint. What do these consist of?

Answer 3

. Tibiofemoral joint and patellofemoral joint
. Tibiofemoral- condyles of femur attach to condyles of tibia
. Patellofemoral- anterior distal part of femur attaches to patella

Question 4

What is the function of the tibiofemoral joint?

Answer 4

Weight-bearing joint

Question 5

What is the function of the patellofemoral joint?

Answer 5

Allows tendon of quadriceps femoris muscles to insert directly over the knee, making the muscles more efficient

Question 6

What does the patella do?

Answer 6

. Acts as fulcrum to increase power of knee extension (via quadriceps muscles)
. Stabilising structure to reduce friction on femoral condyles

Question 7

What is the blood supply of the knee joint?

Answer 7

Genicular anastomoses are around knee, which are supplied by the genicular branches of the femoral and popliteal arteries

Question 8

What is the nerve supply of the knee joint?

Answer 8

. Nerve supply of knee joint is the nerves of the muscles which cross the joint
. Femoral, tibial, common fibular

Question 9

What are the knee menisci? Why are they important? How many are there in the knee?

Answer 9

. C-shaped fibrocartilage bands in knee that increase joint stability and act as shock absorbers by increasing surface are to dissipate forces and pressure
. Two in the knee: medial and lateral

Question 10

Where do the menisci in the knee attach?

Answer 10

. Lateral meniscus has both ends attached to intercondylar area of tibia
. Medial meniscus attached to intercondylar area of tibia and tibial collateral ligament

Question 11

What does damage to the tibial collateral ligament often result in?

Answer 11

Tear in medial meniscus

Question 12

Describe the relative sizes of the knee menisci.

Answer 12

Medial meniscus is bigger than the lateral meniscus

Question 13

What is a bursa?

Answer 13

A synovial fluid-filled sac found between moving structures in a joint (reduce wear and tear on these structures)

Question 14

How many bursae are there in the knee? Name them.

Answer 14

4 bursae in the knee- suprapatella, pre-patella, infrapatella (superficial and deep), semimembranosus

Question 15

Where is the suprapatella bursa found?

Answer 15

Above the patella between the quadriceps and femur

Question 16

Where is the pre-patella bursa found?

Answer 16

In front of patella between patella and skin

Question 17

Where is the infrapatella bursa found?

Answer 17

. Superficial is between patella ligament and skin

. Deep is between patella ligament and tibia

Question 18

Where is the semimembranosus bursa found?

Answer 18

Posteriorly in knee joint behind femur and tibia

Question 19

Name the 3 main ligaments/groups of ligaments in the knee joint.

Answer 19

Patellar ligament, collateral ligaments, cruciate ligaments

Question 20

What is the patellar ligament? What does it attach to?

Answer 20

Continuation of quadriceps femoris tendon distal to patella, attaches to the tibial tuberosity

Question 21

How many collateral ligaments are there? What is their function?

Answer 21

2 strap-like ligaments (medial/tibial and lateral/fibular), stabilise flexion and extension at knee and prevent excessive medial or lateral movement

Question 22

What are the attachments of the medial/tibial collateral ligament?

Answer 22

Attaches to medial epicondyle of femur and medial condyle of tibia

Question 23

What are the attachments of the lateral/fibular collateral ligament?

Answer 23

Attaches to lateral epicondyle of femur and depression on lateral surface of fibular head

Question 24

How many cruciate ligaments are there? What do they do?

Answer 24

There are two cruciate ligaments (anterior and posterior), which cross eachother (hence ‘cruciate’) to connect the femur and tibia

Question 25

What is the function of the anterior cruciate ligament?

Answer 25

Prevents anterior dislocation of tibia

Question 26

What is the function of the posterior cruciate ligament?

Answer 26

Prevents posterior dislocation of tibia

Question 27

What are the attachments of the anterior cruciate ligament?

Answer 27

Originates from intercondylar fossa of femur, attaches to anterior intercondylar region of tibia, where it blends with the medial meniscus

Question 28

What are the attachments of the posterior cruciate ligament?

Answer 28

Originates from medial femoral condyle, attaches to intercondylar region of tibia

Question 29

What are the main movements at the knee joint?

Answer 29

Flexion and extension, medial and lateral rotation

Question 30

How is extension at the knee achieved?

Answer 30

Contraction of quadriceps femoris (Vastus medialis, vastus intermedius, vastus lateralis, rectus femoris), which inserts into tibial tuberosity

Question 31

How is flexion at the knee achieved?

Answer 31

Contraction of hamstrings, gracilis, Sartorius, popliteus

Question 32

How is lateral rotation at the knee achieved?

Answer 32

Contraction of biceps femoris

Question 33

How is medial rotation at the knee achieved?

Answer 33

Contraction of semimembranosus, semitendinosus, gracilis, Sartorius, and popliteal muscles

Question 34

When can medial and lateral rotation occur in the knee?

Answer 34

Only when the knee is flexed. If it isn’t flexed, the rotation occurs at the hip.

Question 35

What is the most common injury to the knee joint? How is this injury assessed?

Answer 35

. Injury to collateral ligaments caused by force applied to side of knee when foot placed on ground

. Assessed by asking patient to medially and laterally rotate leg
. Pain on medial rotation indicates damage to medial ligament, pain on lateral rotation indicates damage to lateral ligament

Question 36

What else is usually damaged when the medial collateral ligament is damaged?

Answer 36

Medial meniscus is usually torn, due to their attachement

Question 37

How is the anterior cruciate ligament torn? How do you test for this?

Answer 37

. Hyperextension of knee or big force to back of knee with joint partly flexed
. Test using anterior drawer test, where you try to pull the tibia forward. If it moves, this ligament has been torn

Question 38

What is the dashboard injury?

Answer 38

When knees flexed and large force applied to shins, pushing tibia backwards

Question 39

How do you test for posterior cruciate ligament damage?

Answer 39

Posterior drawer test, hold knee in flexed position and push tibia posteriorly. If there’s movement, this ligament has been torn.

Question 40

What is bursitis?

Answer 40

Inflammation of bursae

Question 41

What is the unhappy triad? When does it usually occur

Answer 41

. Medial collateral ligament and medial meniscus are joined, so damage to either can affect both structures
. Large lateral force applied to knee joint when knee extended can damage anterior cruciate ligament too, which completes the triad