FAST REVISION
Pathology
The expansion of the marrow space due to increased hematopoiesis can lead to resorption of the outer cortical bone and the formation of new bone, resulting in the characteristic "crew cut" appearance on X-rays. This appearance is due to the trabecula
General Pathology
The primary defect in sickle cell anemia is the replacement of glutamic acid by valine in the ?-chain of hemoglobin, leading to the sickling of red blood cells.