Histology of the developmental process of the femoral diaphysis and its pathological significance in broiler chickens.

Investigation was carried out on the developmental process of the femoral diaphysis in broiler chickens ranging from 1 to 90 days of age. The diaphysis was formed mainly by apposition of newly formed bone tissue resulting from periosteal osteogenesis around the embryonic bone. Endosteal osteogenesis for the diaphysis, on the other hand, was merely concerned with modification of the inner surface. The bone tissue reached the maturing stage at 55 days of age at the earliest. The feature of maturity was recognized at 70 days of age or later. During the developmental period, especially in the active stage, there were distinct differences in the degree of development and thickness between the anterior and posterior parts of the diaphysis. Based on these findings, discussion was made on several diseases and lesions which are characterized by abnormal periosteal and endosteal osteogeneses.