ARRT Lower Extremity Procedures 3

Question 1

For an AP projection of the toes, the central ray is directed perpendicular to the IR at which point?

Accepted Answer

The third metatarsophalangeal joint

Answer

The CR is directed perpendicular to the IR at the third MTP joint, centering the image on the toe joints of interest.

Question 2

During a stress inversion projection of the ankle, which ligament injury is being evaluated?

Accepted Answer

Lateral collateral ligament complex (ATF, CF, PTF)

Answer

Inversion stress testing evaluates the lateral collateral ligament complex, primarily the anterior talofibular and calcaneofibular ligaments.

Question 3

For the plantodorsal (axial) projection of the calcaneus, the central ray is angled approximately how many degrees cephalad to the long axis of the foot?

Accepted Answer

40 degrees

Answer

The CR is angled 40 degrees cephalad to the long axis of the foot to project the calcaneus in the axial plantodorsal view.

Question 4

For a true AP projection of the hip, the lower limb is rotated internally approximately how many degrees to place the femoral neck parallel to the IR?

Accepted Answer

15 degrees

Answer

Internal rotation of 15 degrees corrects for the normal anteversion of the femoral neck, placing it parallel to the IR and reducing foreshortening.

Question 5

Which projection is used to best evaluate the patellofemoral joint space for chondromalacia patellae?

Accepted Answer

Tangential (sunrise/skyline) projection of the patella

Answer

The tangential (sunrise or Merchant) projection profiles the patellofemoral joint, evaluating patellar tracking and cartilage integrity.

ARRT - American Registry of Radiologic Technologists Practice Test

ARRT - American Registry of Radiologic Technologists Practice Test

ARRT Lower Extremity Procedures 3