knee pt 2

Question 2

find diagram and label all parts of femur, knee, tib and fib

Question 3

why must the knee be internally rotated for an ap knee xray

Answer 3

so the femoral condyles are equidistant from plate and patella is central

Question 4

what should be seen on a ap knee xray

Answer 4

• femoral and tibial condyles symmetrical
• head of fibula slightly superimposed by lateral tibial condyle
• patella sits centrally and superimposes distal femur (normally)

Question 5

why is the tube slightly angled cranially 5 degrees for a lateral knee xray

Answer 5

so we can see a clear joint space

Question 6

what should you see on a lateral knee xray

Answer 6

• patella clear of femur
• femoral condyles superimposed
• proximal tibia-fibular joint isnt clearly visible as 1/3 of fib head is superimposed behind tib

Question 7

what is the purpose of bursae in the knee

Answer 7

• reduce friction between moving structures

Question 8

how many bursae does the knee have and what are tehy

Answer 8

4
- supra patella bursa
- pre patella bursa
- infra patella bursa
- pes anserine bursa

Question 9

how might you tell if there is a joint effusion

Answer 9

if the bursa becomes distended more than 1cm

Question 10

why must the knee not be flexed too much on a lateral projection

Answer 10

otherwise the bursa cannot be assessed accurately

Question 11

why must the leg be internally rotated for an ap tib and fib projection

Answer 11

so the femoral condyles are equidistant from the IR

Question 12

What should be seen on a ap tib and fib projection

Answer 12

• entire tib and fib with knee and ankle joint
• soft tissue margin
• tib and fib should be seen separately except at articular ends

Question 13

what will happen if theres under rotation for lateral tib and fib / knee

Answer 13

• fib head sits anteriorly and is completely superimposed by tibia
• joint space not clear and open

Question 14

what will happen if there is over internal rotation for ap tib and fib

Answer 14

• lateral condyle of tib does not superimpose the head of fibula
• knee joint space is not clear and open

Question 15

what will happen if theres over rotation on lateral knee

Answer 15

• fib head isnt projected posteriorly and it doesnt overlap tibia

Question 16

how is the adductor tubercle placed in comparison to the linea aspera

Answer 16

The adductor part attaches distally to the linea aspera, just superior to the medial femoral condyle

Question 17

what is osteochondritis dissencans

Answer 17

joint condition in which bone underneath the cartilage of a joint dies due to lack of blood flow

Question 18

what degree of cranial tube angulation can help superimpose the femoral condyles on a lateral knee xray

Answer 18

5-7 degrees

Question 19

how can you tell if there is over or under rotation in lateral xray knee

Answer 19

over rotation = fibula is projected too posteriorly

under rotation = fibular head is hidden behind tibia

(correct rotation = just slight part of head of fibula is superimposed by tibia)

Question 20

if there is insufficient flexion of knee for a skyline view, what is seen

Answer 20

tibial tuberosity overshadow the retropatella joint

Question 21

if there is too much flexion of knee in skyline view, what is seen

Answer 21

patella will track over the lateral femoral condyle