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
'Hair on end' appearance in X- ray is characteristic of: 
Select and explain. 
A. G6PD deficiency, B. Sickle cell anemia, C. Rickets, D. Scurvy
B: Sickle cell anemia
Answer: B: Sickle cell anemia 
Explanation: Ans. B. Sickle cell anemiaHair on end appearance of the skull is a characteristic feature of chronic Haemolysis usually seen in patients with thalassemia and sickle cell anaemia. It results from accentuated vertical trabeculae between the inner and outer tables of the skull because of excessive bone marrow hyperplasia. Conditions where 'Hair on End Appearance' is seen:Mnemonic: HI NEST* Hereditary spherocytosis* Neuroblastoma* Enzyme deficiency (e.g. G-6-P deficiency causing haemolytic anaemia)* Sickle cell disease* Thalassemia major