ARRT Lower Extremity Procedures 4 — Questions and Answers
Question 1: When imaging the entire femur in one projection, the standard AP requires the central ray to be directed to:
- The mid-femur, with the IR centered accordingly (Correct answer)
- The lesser trochanter
- The distal femur only
- The greater trochanter
Correct answer: The mid-femur, with the IR centered accordingly
The CR is directed to the mid-femur with the IR placed to include both hip and knee joints on a single long image.
Question 2: For the AP projection of the knee, the CR is typically angled how many degrees cephalad in an average patient?
- 0 degrees (perpendicular)
- 5-7 degrees cephalad (Correct answer)
- 10-15 degrees cephalad
- 5-7 degrees caudad
Correct answer: 5-7 degrees cephalad
A 5–7 degree cephalad CR angulation parallels the tibial plateau slope, opening the joint space on an average knee AP.
Question 3: For an AP weight-bearing projection of the foot, the patient stands with the foot flat and the CR is directed:
- Perpendicular to the IR (Correct answer)
- 15 degrees posteriorly (toward the heel)
- 15 degrees anteriorly (toward the toes)
- 30 degrees cephalad
Correct answer: Perpendicular to the IR
For weight-bearing AP foot projections, the CR is perpendicular to the IR to evaluate the arches under physiologic load.
Question 4: Which of the following best describes the position for the lateral projection of the knee?
- Patient supine, knee extended, medial side down
- Patient lateral recumbent, affected side down, knee flexed 20-30 degrees (Correct answer)
- Patient prone, knee extended, lateral side down
- Patient lateral recumbent, affected side up, knee flexed 90 degrees
Correct answer: Patient lateral recumbent, affected side down, knee flexed 20-30 degrees
For a lateral knee, the patient lies with the affected side down, knee flexed 20–30 degrees, and the CR perpendicular to the joint space.
Question 5: For an AP projection of the lower leg (tibia-fibula), which anatomical landmarks should be included on the image?
- Only the mid-shaft of the tibia and fibula
- The knee joint only
- Both the knee and ankle joints (Correct answer)
- The ankle joint only
Correct answer: Both the knee and ankle joints
A complete AP lower leg image must include both the knee and ankle joints to assess the full length of the tibia and fibula.
Question 6: The Kite method is used in pediatric radiography to evaluate which condition of the foot?
- Pes planus (flat foot)
- Talipes equinovarus (clubfoot) (Correct answer)
- Hallux valgus (bunion)
- Metatarsus adductus
Correct answer: Talipes equinovarus (clubfoot)
The Kite method uses AP and lateral projections of both feet simultaneously to evaluate the talocalcaneal angle in clubfoot (talipes equinovarus).
Question 7: For the AP oblique projection of the foot in lateral rotation, the foot is rotated laterally approximately how many degrees?
- 15 degrees
- 30-40 degrees (Correct answer)
- 45-60 degrees
- 90 degrees
Correct answer: 30-40 degrees
A 30–40 degree lateral oblique rotation of the foot separates the metatarsals and demonstrates the interosseous spaces and lateral tarsal bones.
ARRT Lower Extremity Procedures 4
When imaging the entire femur in one projection, the standard AP requires the central ray to be directed to: