Week 11 - Knee Anatomy and Radiography Techniques

These flashcards cover key concepts related to knee anatomy and radiographic techniques, ensuring thorough preparation for the exam.

What is the bony protrusion on the front of the pelvis called?

Anterior Superior Iliac Spine (ASIS)

What angle is the CR for a standard knee AP based on pelvic thickness of 19-24 cm?

Perpendicular

Where should the central point (CP) be located for a knee AP projection?

1 cm distal to the patellar apex.

What structure is included in the knee AP projection?

Distal 1/4 femur, patella, and proximal 1/4 tibia and fibula.

What is the main goal when positioning for a knee AP?

To ensure the anterior and posterior tibial margins are superimposed and the femorotibial joint is open.

What indicates correct internal rotation when positioning for a knee AP?

The femoral epicondyles should be equidistant to the IR.

What angle should the knee be flexed for a lateral knee projection?

20-30 degrees.

What is the CR angle for a lateral knee projection?

5-7 degrees cephalad.

For an AP oblique knee medial rotation, how should the leg be positioned?

Rotate the affected leg 45 degrees medially.

What is the goal for positioning in an AP oblique knee (lateral rotation)?

Fibular head free of the tibia.

What structure must be included in a lateral knee projection?

Patellar ligament insertion at the tibial tuberosity.

What is the CP for a lateral knee x-ray?

2.5 cm distal to the medial femoral condyle.

What denotes appropriate positioning for a lateral knee?

Patella free from femur and femoral condyles superimposed.

What method is used to open the knee joint space during a lateral knee x-ray?

Angle the CR 5-7° cephalad.

What should you assess to ensure no rotation of the knee?

Check that the femoral condyles are aligned and the patella is perpendicular to the IR.

What structure indicates potential injury when assessing a knee x-ray?

Fat pads.

In a medial rotation PA oblique knee, how should the hip be positioned?

Elevate the unaffected hip with a support sponge.

What is the CR for a weightbearing knee x-ray?

Perpendicular.

What CP is used for a bilateral weightbearing knee x-ray?

1 cm inferior to patellar apex, midline between the two knees.

What imaging might show narrowing of joint space not visible in non-weightbearing knees?

Weightbearing knee x-rays.

What is the significance of the tibial plateau in knee imaging?

It is crucial for assessing knee joint space and injuries.

Why is complete extension of the knee important during x-ray?

To avoid displacement of fragments or injury to vasculature.

What is a risk of excessive knee flexion during imaging?

It can obscure view of joint effusion and displace fat pads.

How should the unaffected leg be positioned in a lateral knee projection?

Bend it anterior to the affected leg for better control.

What does the term 'SI' refer to in radiographic positioning?

Superimposition.

In an AP oblique knee, what should be visible in adequate rotation?

Half of the patella should be free from superimposition with the medial condyle.

For the lateral knee, what positioning is critical for visualization of the patellofemoral joint?

Keep the knee flexed under 30 degrees.

What is the importance of proper beam angling in knee imaging?

To accurately visualize the joint space and avoid rotational artifacts.

What is the effect of knee flexion on the relationship between tibia and fibula?

The tibia moves posteriorly.

What technique can help prevent rotation during lateral knee positioning?

Use a sponge against the lateral aspect of the ankle.