Figure 1

Photomicrograph of femoral head (A, B) and femoral condylar (C, D) bone marrow. (A) Control chicken at 19 weeks. There are appropriate fatty cells and vacuoles. Thickened primary bone trabeculae with secondary bone trabeculae are seen (H & E). (B) Experimental chicken 19 weeks after steroid injection. There is evidence of proliferation of fatty vacuoles. Thinned primary bone trabeculae, with replacement by secondary bone trabeculae are seen (H & E). (C) Control chicken at 19 weeks (the same control chicken as in Figure 1A). The section shows fatty cells and bone trabeculae (H & E). (D) Experimental chicken 19 weeks after steroid injection (the same experimental chicken as in Figure 1B). The section shows obvious increase in fatty vacuoles. There is evidence of loss of primary bone trabeculae, which have been replaced by marked secondary bone trabeculae with nodular formation (arrow) (H & E).