This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Orthopaedics
Radiological sign of spondylolysis is 
Select and explain. 
A. Napoleon's hat sign, B. 'Scottsh dog with collar' sign, C. Winking owl sign, D. 'Cap' sign
B: 'Scottsh dog with collar' sign
Answer: B: 'Scottsh dog with collar' sign 
Explanation: Spondylolysis is a defect or fracture of the pars interaicularis. On the "Scotty dog" view, it is seen as a band of radiolucency through the "neck," like a collar. Ref: Maheshwari 6e pg 224,262,284.