How can improper positioning affect evaluation of the lumbar spine on radiographs?

• A. Causes distortion, rotation, and misinterpretation of alignment or pathology.
• B. Improves contrast by reducing scatter.
• C. Reduces patient dose.
• D. Confines the study to a single vertebral level.

Answer: (A)

Positioning determines projection geometry, so improper positioning of the lumbar spine on radiographs leads to distortion and rotation on the image, which in turn causes misinterpretation of alignment or pathology. When the AP view is not properly centered or the patient is rotated, vertebral bodies and pedicles can appear off the midline, fake scoliosis, and obscure or exaggerate relationships between vertebrae, making it hard to assess listhesis, facet joints, or alignment. In the lateral view, incorrect centering or flexion/extension can blur or misrepresent vertebral height and posterior elements, masking fractures or degenerative changes. Contrast and scatter control, as well as patient dose considerations and study coverage, are not improved by poor positioning; improper positioning often requires repeats (increasing dose) and does not inherently limit or refine the region imaged.