This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal system, Subject name: Radiology
Bamboo spine is seen in - 
Select and explain. 
A. Ankylosing spondylitis, B. RA, C. Paget's disease, D. Fibrous dysplasia
A: Ankylosing spondylitis
Answer: A: Ankylosing spondylitis 
Explanation: Radiological features of Ankylosis spondylitis are : Sacroiliitis Enthesopathy Romanus lesions Bamboo spine Rugger Jersy spine Interveebral disc calcification Dagger sign Trolley track sign Squarring of veebrae.