[Objective] This study aimed to investigate the differences in morphological structure of tibias between sick and normal ostrich chicks. [Method] Normal and sick ostrich chicks aged 90 days were used in this research for bone mineral density determination, bone demineralization paraffin section preparation （HE staining）, bone abrasive disc preparation and scanning electron microscopy （SEM） observation, to analyze the differences in microstructure and ultrastructure of tibias between sick ostrich chicks and normal ones. [Result] Bone mineral density of ostrich chicks suffering from leg disease was much lower than that of the normal ones. Compared with normal tibias, less trabeculae were observed in sick tibias, which were attenuated and began to disappear. In addition, trabeculae micro-fracture could be observed under scanning electron microscope; resorption pits on bone slices formed by osteoclast could be observed under scanning electronic microscope. [Conclusion] These results indicate that the sick tibias all have lower bone density and trabeculae microfracture phenomenon in tibias with different diseases, which might be resulted from osteoporosis.
