Beheaded Scottish terrier sign is –
Oblique view of spine displays the lamina and articular processes more clearly than the classical anteroposterior & lateral views. The shadow of the neural arch resembles that of Scottish terrier dog.
Spondylolysis          → Scotty dog wearing a collar sign.
Spondylolisthesis     → (i) Beheaded Scotty dog sign;

                                                (ii) 'Inverted Napoleon's Hat' sign.
Spondylosis
Spondylolisthesis
Lumbar canal stenosis
Slipped disc