The Knee

Question 1

Describe the knee joint

Answer 1

The knee joint is a bicondylar type synovial joint, which mainly allows for flexion and extension (and a small degree of medial and lateral rotation). It is formed by articulations between the patella, femur and tibia.

Question 2

What are the two articulations of the knee joint?

Answer 2

Tibiofemoral – The medial and lateral condyles of the femur articulating with the tibia.

Patellofemoral – The anterior and distal part of the femur articulating with the patella.

Question 3

Which joint is weight-bearing within the knee?

Answer 3

The tibiofemoral joint is the weight-bearing joint of the knee.

Question 4

What are the functions of the medial and lateral menisci?

Answer 4

The medial and lateral menisci are fibrocartilage structures in the knee that serve two functions:

• To deepen the articular surface of the tibia, thus increasing stability of the joint.
• To act as shock absorbers. They are C shaped, and attached at both ends to the intercondylar area of the tibia.

Question 5

Describe the menisci of the knee

Answer 5

In addition to the intercondylar attachment, the medial meniscus is fixed to the tibial collateral ligament and the joint capsule. Any damage to the tibial collateral ligament results in tearing of the medial meniscus.

The lateral meniscus is smaller and does not have any extra attachments, rendering it fairly mobile.

Question 6

What is a bursa?

Answer 6

A bursa is synovial fluid filled sac, found between moving structures in a joint – with the aim of reducing wear and tear on those structures.

Question 7

What is the suprapatella bursa?

Answer 7

Suprapatella bursa – This is an extension of the synovial cavity of the knee, located between the quadriceps femoris and the femur.

Question 8

What is the pre patella bursa?

Answer 8

Prepatella bursa – Found between the apex of the patella and the skin.

Question 9

What is the infra patella bursa?

Answer 9

Infrapatella bursa – Split into deep and superficial. The deep bursa lies between the tibia and the patella ligament. The superficial lies between the patella ligament and the skin.

Question 10

What is the semimebranosus bursa?

Answer 10

Semimembranosus bursa – Located posteriorly in the knee joint, between the semimembranosus muscle and the medial head of the gastrocnemius.

Question 11

What are the major ligaments in the knee joint?

Answer 11

• Patellar ligament
• Collateral ligaments
• Cruciate ligaments

Question 12

What is the patellar ligament?

Answer 12

Patellar ligament – A continuation of the quadriceps femoris tendon distal to the patella. It attaches to the tibial tuberosity.

Question 13

What are the collateral ligaments?

Answer 13

Collateral ligaments – These are two strap-like ligaments. They act to stabilise the hinge motion of the knee, preventing any medial or lateral movement
Tibial (medial) collateral ligament and the fibular (lateral) collateral ligament.

Question 14

What are the cruciate ligaments?

Answer 14

Cruciate Ligaments (anterior and posterior) – These two ligament connect the femur and the tibia. In doing so, they cross each other, hence the term ‘cruciate’ (Latin for like a cross)

Question 15

What are the four main movements of the knee joint?

Answer 15

• Extension
• Flexion
• Lateral rotation
• Medial rotation

Question 16

What is the tibial (medial) collateral ligament?

Answer 16

A wide and flat ligament, found on the medial side of the joint. Proximally, it attaches to the medial epicondyle of the femur, distally it attaches to the medial surface of the tibia.

Question 17

What is the fibular (lateral) collateral ligament?

Answer 17

Thinner and rounder than the tibial collateral, this attaches proximally to the lateral epicondyle of the femur, distally it attaches to a depression on the lateral surface of the fibular head.

Question 18

What is the anterior cruciate ligament?

Answer 18

Anterior cruciate ligament – attaches at the anterior intercondylar region of the tibia and ascends posteriorly to attach to the femur, in the intercondylar fossa. It prevents anterior dislocation of the tibia onto the femur.

Question 19

What is the posterior cruciate ligament?

Answer 19

Posterior cruciate ligament – attaches at the posterior intercondylar region of the tibia, and ascends anteriorly to attach to the femur in the intercondylar fossa. It prevents posterior dislocation of the tibia onto the femur.

Question 20

How is the knee extended?

Answer 20

• Extension: Produced by the quadriceps femoris, which inserts into the tibial tuberosity.

Question 21

How is the knee flexed?

Answer 21

• Flexion: Produced by the hamstrings, gracilis, sartorius and popliteus.

Question 22

How is the knee laterally rotated?

Answer 22

• Lateral rotation: Produced by the biceps femoris.

Question 23

How is the knee medially rotated?

Answer 23

• Medial rotation: Produced by five muscles; semimembranosus, semitendinosus, gracilis, sartorius and popliteus.