CAMRT Radiography Practice Exam

What is the reason for the distance discrepancy between the left pedicles and the spinous process on an AP Lumbar projection?

1. The patient was rotated toward the left side (LPO rotation)

2. The patient was rotated toward the right side (RPO rotation)

3. The patient was in the supine position

4. Incorrect central ray angulation

The correct answer is: The patient was rotated toward the right side (RPO rotation)

When evaluating an AP Lumbar projection, the distance discrepancy between the left pedicles and the spinous process typically indicates that the patient was rotated toward the right side (RPO rotation). This rotation affects the positioning of the vertebrae, leading to a misalignment that causes the left pedicles to appear closer together than the spinous process. In a standard AP view with proper positioning, the spinous processes should be centered and equidistant from the pedicles on either side, appearing symmetrical. However, if the patient is rotated to the right, the left pedicles move further away from the midline, while the spinous process remains relatively centered, creating the observed discrepancy. Thus, recognizing patient rotation is key in radiographic interpretation. Proper positioning is crucial to obtaining accurate and diagnostic images, and understanding the implications of rotation helps ensure that radiographers can identify and correct errors in patient alignment before exposure.