Study on the influence of the injury of epiphysis to metaphysis in young growing rats.

The influence of partial excision at the proximal epiphysis of the tibia to metaphysis in young growing rats were investigated from 2 days to 8 weeks after excision by roentgenological and histological methods.The results were as follows;1) The longitudinal bone growth of experimental tibia was slightly inhibited while the transverse diameter of metaphysis was remarkably increased compared with normal controls.2) At 2 and 4 days after operation the calcified cartilagenous septa were not seen in the primary spongiosa and many osteoblastic cells were transversely oriented along the growth plate metaphyseal junction. Then at 1 week after operation the calcified cartilagenous septa newly projected into the primary spongiosa, which were shorter in length and thicker in width than normals. Until 4 weeks they gradully increased in length and became same as normals. The peripheral trabeculae of the metaphyseal primary spongiosa which were located under excited epiphysis were arranged obliquely from 2 to 4 weeks. Since 1 week the cells of the deep proliferative zone of cartilagenous epiphysis and the marginal germinative zone of epiphyseal plate were remarkably increased in size and number.