ARRT - American Registry of Radiologic Technologists Lower Extremity Procedures Questions and Answers

Question 1

A patient arrives in the emergency department with a traumatic injury to the hip and is unable to move the affected leg. To obtain a lateral projection of the proximal femur, which of the following methods should the technologist employ?

Accepted Answer

Axiolateral inferosuperior (Danelius-Miller method)

Answer

The axiolateral inferosuperior projection, also known as the Danelius-Miller or cross-table lateral method, is specifically designed for trauma situations where the patient cannot move the affected leg. [7, 11, 12, 17] It provides a lateral view of the femoral head, neck, and trochanters by directing the central ray horizontally, avoiding the need for patient manipulation.

Question 2

When evaluating an AP pelvis radiograph for proper positioning, which of the following indicates the patient was not rotated?

Accepted Answer

The iliac alae and obturator foramina are symmetric.

Answer

Symmetry of the iliac alae (wings) and the obturator foramina is the primary indicator that the pelvis is not rotated. [3, 4] If one iliac ala appears wider and the corresponding obturator foramen appears more closed, it signifies rotation toward that side.

Question 3

A radiograph of an AP oblique foot demonstrates significant overlapping of the bases of the third, fourth, and fifth metatarsals. Which of the following is the most likely cause of this appearance?

Accepted Answer

Excessive medial rotation of the foot.

Answer

The goal of the AP oblique projection of the foot is to separate the metatarsals, typically requiring 30-40 degrees of medial rotation. [19, 33] When the bases of the lateral metatarsals are excessively overlapped, it indicates the foot was rotated too much, exceeding the optimal degree of obliquity. [24]

Question 4

An emergency room physician orders an ankle series to evaluate the integrity of the entire ankle mortise. Which projection is specifically performed to demonstrate an open tibiotalar and distal tibiofibular joint?

Accepted Answer

AP oblique with 15-20 degree medial rotation

Answer

The AP oblique projection with 15-20 degrees of medial rotation is known as the mortise view. [6, 15, 22, 23] This specific degree of rotation places the intermalleolar line parallel to the image receptor, which opens the entire ankle mortise joint for evaluation without bony overlap.

Question 5

Which of the following projections is specifically designed to demonstrate the intercondylar fossa of the femur, often referred to as a 'tunnel' view?

Accepted Answer

PA axial (Camp-Coventry method)

Answer

The PA axial (Camp-Coventry method), along with other methods like the Holmblad, are 'tunnel' views designed to project the central ray directly through the intercondylar fossa. [5, 8] This requires patient positioning that involves significant knee flexion to visualize the fossa without superimposition from the patella. [10, 16]

ARRT - American Registry of Radiologic Technologists Practice Test

ARRT - American Registry of Radiologic Technologists Practice Test

ARRT - American Registry of Radiologic Technologists Lower Extremity Procedures Questions and Answers