严重的慢性贫血症（如地中海贫血症和镰状细胞贫血症）可增强骨髓生成RBC的能力，促进骨髓增生，使骨髓所在部位发生变化，如图可见异常的颅骨，骨髓增生使颅骨形状发生变化(前额隆起或额头突出)。
Severe, chronic anemias (such as thalassemias and sickle cell anemia) can increase the bone marrow response to form RBC's. This drive for erythropoiesis may increase the mass of marrow and lead to increase in marrow in places, such as the skull seen here, that is not normally found. Such an increase in marrow in skull may lead to "frontal bossing" or forehead prominence because of the skull shape change.
