Knee Positioning Flashcards
What IR is used for knee views?
10x12
What SID is used for knee views?
40”
What are the structures seen for an AP knee?
- AP of knee joint including proximal tib-fib articulation
- Symmetric femoral condyles and tibial intercondylar eminence is centered
- Patella completely superimposed on the femur
- Open femorotibial joint space
- Include distal femur and proximal tib-fib
How is the patient positioned for an AP knee?
Patient supine with femoral condyles parallel to IR
How do you find the tube angle for an AP knee?
By measuring the pelvis thickness through the ASIS
What are the tube angles when determining from pelvis thickness?
- <19 cm: 3-5 degrees caudal
- 19-24 cm: 0 degrees
- > 24 cm: 3-5 degrees cephalic
Where is the CR for an AP knee?
Centered to knee 1/2” distal to apex of patella
How many degrees is the CR angled for an AP knee?
Determined by ASIS measurement
What are the structures seen for a 45-degree medial oblique knee?
- Tibia and fibula separated ar their proximal articulation
- Lateral femoral & tibial condyles
- Both tibial plateaus
- Open knee joint
- Margin of the patella projecting slightly beyond the medial side of the femoral condyle
- Include distal femur & proximal tib-fib
How is the patient positioned for a 45-degree medial oblique knee?
- Patient supine with ankle supported
- Medially rotate the entire lower limb 45-degrees
- Elevate the hip
Where is the CR for a 45-degree medial oblique knee?
Centered to knee 1/2” distal to apex of patella
How many degrees is the CR angled for a 45-degree medial oblique knee?
Angle depends on ASIS meaurement
What are the structures seen for a 45-degree lateral oblique knee?
- Medial femoral and tibial condyles seen
- Fibula superimposed over the lateral half of the tibia
- Open knee joint
- Both tibial plateaus seen
- Margin of the patella projecting slightly beyond the lateral side of the femoral condyle
- Include distal femur and proximal tib-fib
How is the patient positioned for a 45-degree lateral oblique knee?
- Patient supine with ankle supported
- Laterally rotate the entire lower limb 45-degrees
- Elevate the hip
Where is the CR for a 45-degree lateral oblique knee?
Centered to knee 1/2” distal to apex of patella
How many degrees is the CR angled for a 45-degree lateral oblique knee?
Angle depends on ASIS measurement
What are the structures seen for a mediolateral knee?
- Femoral condyles superimposed
- Open joint space between femoral condyles and tibia
- Patella in profile
- Open patellofemoral joint
- Fibular head and tibia slightly superimposed
- Include distal femur and proximal tib-fib
Where is the CR for a mediolateral knee?
1” distal to medial epicondyle
How is the patient positioned for a mediolateral knee?
- From supine position, patient is rolled up onto affected side
- Place unaffected leg behind or in front of the affected knee
- Femoral condyles perpendicular to IR
- Knee flexed 20-30 degree
How many degrees is the CR angled for a mediolateral knee?
5-7 degrees cephalic
