Hair-on-end appearance in a skull roentgenogram is seen in:

 # " Hair-on-end" appearance in a skull roentgenogram is seen in:

a. Fibrous dysplasia 

b. Thalassemia 

c. Garre's Osteomyelitis 

d. Paget's Disease 

The correct answer is B. Thalassemia.

Similar to sickle cell anemia, the features of thalassemia generally result from hyperplasia of the ineffective bone marrow and its subsequent failure to produce normal red blood cells. However, these changes are usually more severe than with other anemias. There is a generalized radiolucency of the long bones with cortical thinning. In the skull, the diploic space exhibits marked thickening, especially in the frontal region. The skull also shows a generalized granular appearance, and occasionally a “hair-on-end” effect may develop.