ARRT - American Registry of Radiologic Technologists Upper Extremity Procedures Questions and Answers — Questions and Answers
Question 1: A patient arrives in the emergency department with a traumatic injury to their elbow and is unable to extend it for a standard AP projection. To best demonstrate a potential fracture of the radial head, which specialized projection should be performed?
- Inferosuperior axial projection (Lawrence method)
- PA oblique projection (Scapular Y)
- AP oblique projection (Grashey method)
- Axiolateral projection (Coyle method) (Correct answer)
Correct answer: Axiolateral projection (Coyle method)
The Coyle method is a specific trauma projection used to evaluate the radial head and coronoid process when the patient cannot extend their elbow. It involves flexing the elbow 90 degrees and angling the central ray 45 degrees toward the shoulder, which projects the radial head free of superimposition.
Question 2: An AP oblique projection of the shoulder (Grashey method) is performed primarily to demonstrate which of the following?
- The acromioclavicular (AC) joint without superimposition.
- The relationship of the humeral head to the glenoid cavity for dislocation.
- An open glenohumeral joint space. (Correct answer)
- The lesser tubercle in profile.
Correct answer: An open glenohumeral joint space.
The primary purpose of the Grashey method is to place the glenoid cavity in profile, thereby demonstrating an open glenohumeral joint space. This is achieved by rotating the patient 35 to 45 degrees toward the affected side. This view is excellent for evaluating joint space narrowing associated with arthritis.
Question 3: A radiographer is performing a PA projection of the wrist for a suspected scaphoid fracture. Which specific positioning maneuver is critical to best visualize the scaphoid bone free of foreshortening and superimposition?
- Radial deviation
- Ulnar deviation (Correct answer)
- Placing the hand in a fist
- Hyperextension of the wrist
Correct answer: Ulnar deviation
Ulnar deviation of the wrist elongates the scaphoid and opens the intercarpal spaces, particularly around the scaphoid. This movement corrects the natural foreshortening of the scaphoid that occurs in a neutral PA position, providing a clearer view for fracture assessment.
Question 4: Which of the following upper extremity projections is performed to evaluate for a suspected dislocation of the shoulder by demonstrating the relationship of the humeral head to the glenoid fossa in a true lateral perspective of the scapula?
- Transthoracic lateral projection (Lawrence method)
- AP oblique projection (Grashey method)
- PA oblique projection (Scapular Y) (Correct answer)
- AP axial projection (Stryker notch method)
Correct answer: PA oblique projection (Scapular Y)
The PA oblique (Scapular Y) projection provides a lateral view of the scapula. The 'Y' is formed by the acromion, coracoid process, and the body of the scapula. The humeral head should be superimposed over the junction of the 'Y'. This view is essential for determining the direction (anterior or posterior) of a shoulder dislocation.
Question 5: A trauma patient requires a lateral projection of the proximal humerus but cannot abduct their arm. The technologist decides to perform a transthoracic lateral (Lawrence method). What is the proper positioning for the patient's uninjured arm?
- Kept at the patient's side in a neutral position.
- Crossed over the chest to depress the uninjured shoulder.
- Raised above the head. (Correct answer)
- Abducted 45 degrees from the body.
Correct answer: Raised above the head.
For the transthoracic lateral projection, the uninjured arm must be raised above the head. This elevates the uninjured shoulder, preventing its superimposition over the proximal humerus of the injured side, which is being imaged through the thorax.
Question 6: The tangential, inferosuperior projection of the wrist (Gaynor-Hart method) is specifically designed to visualize which anatomical structure?
- The radioulnar joint
- The scapholunate articulation
- The carpal canal (tunnel) (Correct answer)
- The first carpometacarpal joint
Correct answer: The carpal canal (tunnel)
The Gaynor-Hart method is a tangential projection that visualizes the carpal canal (tunnel) in profile. This view is used to assess for bony changes that may be causing carpal tunnel syndrome, such as impinging on the median nerve, and to evaluate for fractures of the pisiform, hamulus of the hamate, and trapezium.
ARRT - American Registry of Radiologic Technologists Upper Extremity Procedures Questions and Answers
A patient arrives in the emergency department with a traumatic injury to their elbow and is unable to extend it for a standard AP projection.
To best demonstrate a potential fracture of the radial head, which specialized projection should be performed?