Fig. 1.

LM micrograph showing an example of a microscopic field in which TUNEL and TEM observations were performed. Cross-section of primary spongiosa around the growing tibial shaft of a 16-day-old chick embryo; the direction of bone growth is from left to right. The arrows point to the sites of differentiation of cords of stationary osteoblasts along the periosteal surface. The bony trabeculae laid down by static osteogenesis appear to be carpeted by typical movable osteoblastic laminae. Scale bar = 35 µm.