The knee joint (dave's notes)

Question 1

What type of joint is the knee? What bones are involved?

Answer 1

A synovial joint between femur and tibia with the patella in front.

Question 2

What are the movements of the knee? What are these movements for?

Answer 2

Extension for propulsion

Flexion for shock absorption

Question 3

Other than extension and flexion, what movement is the knee able to make, and when?

Answer 3

The flexed knee can actively rotate

Question 4

What type of movement occurs when straightening the knee?

Answer 4

Passive inevitable rotation in the screw home mechanism

Question 5

Describe the tibial surface. How does it allow for meniscal movement?

Answer 5

The tibial surface provides two separate concats articular facets, medial on the upper surface of the condyle, lateral becomes convex at the back which allows withdrawal of the lateral meniscus

Question 6

Where is the knee capsule attached to the tibia?

Answer 6

Around the margins of the plateau except posteriorly (attached to ridge and laterally prolonged over the popliteus tendon)

Question 7

Describe the condyles of the femur

Answer 7

The femur has two condyles separated posteriorly by a deep notch but fused anteriorly.

Question 8

Where is the knee capsule attached to the femur?

Answer 8

Below the epiphyseal line down to the articular margin except at

1) the back - it is attached to the intercondylar ridge, and
2) Laterally it encloses the popliteus tendon

Question 9

Describe the thickness of the capsule and its relation to bursae

Answer 9

The capsule varies in thickness. The original capsule perforates and communicates with the large supra patellar bursa (deep to quadriceps tendon). Note the other gap allowing the popliteus tendon to enter.

Question 10

Where does the tendon of popliteus lie?

Answer 10

In between the capsule and the synovial membrane.

Question 11

What is the largest synovial joint in the body? What is the normal volume of synovial fluid?

Answer 11

The knee.

0.5mL approx

Question 12

How does the synovial membrane communicate with the capsule?

Answer 12

The two do not coincide.

Question 13

What does the synovial membrane lining of the knee joint communicate with?

Answer 13

The supra patellar bursa and popliteus membrane, and the bursa beneath the medial head of gastrocnemius (which may also communicate with the semi-membranosus bursa) +/- bursa beneath lateral head of gastrocnemius.

Question 14

What is the blood supply to the knee?

Answer 14

From anastomoses around the knee joint largely from the 5 genicular branches of the popliteal artery

Question 15

What is the nerve supply to the knee?

Answer 15

Femoral (vastus medialis)
Sciatic (genicular branches of the tibia and common peroneal)
Obturator nerve

Question 16

What movement does popliteus initiate? When?

Answer 16

From the locked position, lateral rotation of the femur must precede flexion - this is produced by popliteus.

Question 17

See text for

Answer 17

movements, stability and surgical approach