Which view demonstrates the pars interarticularis in the lumbar region?

Which view demonstrates the pars interarticularis in the lumbar region?

• A. AP Lumbar View
• B. Lateral Lumbar View
• C. PA Lumbar
• D. Lumbar Oblique Projection

Answer: (D)

Visualizing the pars interarticularis requires an oblique view because this rotation places the pars in profile between the articular processes, making it the thin “neck” area that can be seen clearly. When the patient is rotated about 45 degrees, the pars interarticularis projects away from overlapping structures and becomes distinct on the image, which is exactly where a fracture line would appear in spondylolysis. In other views, the pars is more obscured by surrounding bones—the AP and PA views compress and superimpose the posterior elements, while the lateral view presents a different plane that can still hide the pars. The oblique projection minimizes these overlaps and highlights the pars region, making it the best view to evaluate the lumbar pars interarticularis.

Visualizing the pars interarticularis requires an oblique view because this rotation places the pars in profile between the articular processes, making it the thin “neck” area that can be seen clearly. When the patient is rotated about 45 degrees, the pars interarticularis projects away from overlapping structures and becomes distinct on the image, which is exactly where a fracture line would appear in spondylolysis.

In other views, the pars is more obscured by surrounding bones—the AP and PA views compress and superimpose the posterior elements, while the lateral view presents a different plane that can still hide the pars. The oblique projection minimizes these overlaps and highlights the pars region, making it the best view to evaluate the lumbar pars interarticularis.