A morphological study on the sternal development of Korean cattle

한우의 흉골 발생에 관한 형태학적 연구

This study was undertaken to obtain basic data of the sternal development in Korean native cattle from the earliest sternal formation to the ossification using histological and histochemical methods. Thrity three sterna were collected from a series of embryos and fetuses ranging from 11 to 225mm (estimated age 37~120days) in crown rump length. The bilateral sternal bars were observed in the 2nd group(CRL 21~3mm) of Korean cattle embryos. Those bars initiated to be fused in the 3rd group (CRL 31~4mm) and completed in the 7th group(CRL 71~80mm). The ossification centers were detected in the 8th group(CRL 81~90mm) also bilateral ossification centers were found in the same group. The typical epiphyseal plates, endochondral bone and calcium deposit were found in the 9th group(CRL 91~100mm). Osteocytes, osteoblasts, osteoclasts and myeloid cells appeared in ossification centers in the 10th group(more than CRL 101mm). The alcianophility responded markedly in the 9th group that was decreased and showed slightly positive reaction in territorial matrix of the 10th group. Marked positive reaction to PAS was observed in bony trabeculae in the 10th group. The positive reaction to calcium deposit by trichrome stain was observed initially in the hypertrophied zone of epiphyseal plate in the 9th group and was conspicuous in the calcified zone of epiphyseal plate in the 10th group. The 1st positive reaction to the von Kossa stain was observed in the 9th group.