American Society of Radiologic Technologist (ASRT) Practice Exam

In an AP projection of the humerus, the coronal plane passing through the humeral epicondyles must be aligned how relative to the image receptor?

1. Perpendicular

2. Parallel

3. At a 45° angle

4. At a 30° angle

The correct answer is: Parallel

In an AP projection of the humerus, aligning the coronal plane passing through the humeral epicondyles parallel to the image receptor is essential for creating an accurate radiographic image. This alignment ensures that the humerus is correctly projected without any unnecessary distortion, allowing for clear visualization of the anatomical structures. When the epicondyles are parallel to the image receptor, it guarantees that the humerus is in its true anatomic position in the AP view. This positioning is crucial for evaluating any potential pathology, as misalignment can lead to overlapping of structures, making it difficult to assess the details of the humeral shaft and its relationships with surrounding anatomy. Aligning the coronal plane in any other orientation, such as perpendicular or at an angle, would result in distortion of the image and potentially obscure critical information necessary for diagnosis. Thus, maintaining a parallel alignment is key for both clarity and accuracy in diagnostic imaging of the humerus.