American Society of Radiologic Technologist (ASRT) Practice Exam

For a lateral projection of the chest, where does the longitudinal central ray enter?

1. T7; the midcoronal plane

2. T7; the midsagittal plane

3. the midcoronal plane; T7

4. the midsagittal plane; T7

The correct answer is: T7; the midsagittal plane

In a lateral projection of the chest, the central ray is positioned to provide the best view of the thoracic structures, particularly the lungs and mediastinum. The correct placement of the longitudinal central ray is at the level of T7, which is located posteriorly and approximately at the level of the inferior angle of the scapula. This positioning is critical because T7 corresponds to the center of the thoracic cavity, ensuring that the radiographic images capture the lungs without distortion. Additionally, for a lateral view, the midcoronal plane is used to orient the body correctly, allowing for an unobstructed view of the thoracic anatomy. The central ray enters the body at T7 and is perpendicular to the midcoronal plane, which is the standard method of obtaining a lateral chest image. Understanding these anatomical landmarks helps in achieving high-quality images and is a fundamental aspect of radiologic techniques.