ARRT Lower Extremity Procedures 5

Question 1

A patient presents with a suspected Lisfranc injury. Which projection of the foot is most useful for initial evaluation?

Accepted Answer

Weight-bearing AP projection of the foot

Answer

Weight-bearing AP projections best reveal Lisfranc (tarsometatarsal) instability by demonstrating diastasis under physiologic load.

Question 2

For the bilateral frog-leg (modified Cleaves) projection of the hips, the patient's thighs are abducted approximately how many degrees from vertical?

Accepted Answer

40-45 degrees

Answer

The frog-leg position requires 40–45 degrees of bilateral thigh abduction from vertical to profile the femoral necks.

Question 3

Bohler's angle (tuber-joint angle) is assessed on which projection of the calcaneus?

Accepted Answer

Lateral projection

Answer

Bohler's angle (normally 20–40 degrees) is measured on the lateral calcaneus projection and is decreased in calcaneal compression fractures.

Question 4

For the AP projection of the pelvis, the lower limbs are placed in how many degrees of internal rotation?

Accepted Answer

15 degrees

Answer

Internal rotation of 15 degrees counteracts femoral neck anteversion, placing the femoral necks parallel to the IR for a true AP pelvis.

Question 5

Which projection of the knee specifically evaluates the posterior tibial plateau for impaction fractures?

Accepted Answer

Posteroanterior axial (Rosenberg) weight-bearing projection

Answer

The Rosenberg weight-bearing PA flexion view at 45 degrees is sensitive for early joint space narrowing and posterior tibial plateau lesions.

ARRT - American Registry of Radiologic Technologists Practice Test