Scotty dog sign - refers to the normal appearance of the lumbar spine posterior elements when seen on oblique views:
- the transverse process being the nose
- the pedicle forming the eye
- the inferior articular facet being the front leg
- the superior articular facet representing the ear
- the pars interarticularis (the lamina between the facets) equivalent to the neck.
If a spondylolysis is present, the pars interarticularis will have a defect and look like the Scotty dog has a collar - or doggy decapitation for those with a bloodier imagination!