The scotty dog sign is seen on which imaging view?

• A. Oblique lumbar spine radiographs
• B. AP knee radiographs
• C. Lateral thoracic spine radiographs
• D. AP pelvis radiographs

Answer: (A)

The scotty dog sign is seen on the oblique view of the lumbar spine. When the lumbar spine is radiographed obliquely, the posterior elements align to resemble a small dog: the neck corresponds to the pars interarticularis, and a fracture in that area presents as a “collar” on the neck, which is the telltale sign of spondylolysis. This view specifically highlights the pars interarticularis, which is not well seen on the other projection angles listed, so the sign doesn’t appear on AP knee, AP pelvis, or lateral thoracic views.