We used microvascular corrosion cast and scanning electronic microscopy (SEM) to observe the microvascular architecture of femur marrow in Waster rats. The result showed that the central marrow arteries run bilaterally along the marrow space, from which the primary arterioles were given offby tree-like ramifications. The capillaries anastomosed each other to form a densitic capillary network , which expanded gradually and anastomosted to turn into vein sinuse. The vein sinuse gathered to become collective v...