The relative contribution of individual osseous circulations to diaphyseal cortical blood supply.

The potential contributions of periosteal, nutrient (medullary), and epiphyseo-metaphyseal circulations, respectively, to cortical blood supply have been investigated by isolating each using a diaphyseal segment model. The periosteal circulation was isolated by creating and nailing a 2-cm segment of the adult rabbit tibial diaphysis. The medullary circulation was isolated by external application of a silastic sheath to a diaphyseal segment. The epiphyseo-metaphyseal circulation was isolated by combining both techniques. The residual potential routes of blood supply to each isolated segment were studied by arterial radiography and by histology in a postmortem study and in a survival study at various times up to 4 weeks after the isolation procedure. Both centrifugal and centripetal arterial supply were observed in the postmortem study. In the survival study, cortical arterial perfusion was observed up to 4 weeks following isolation of the periosteal circulation but only up to 2 weeks following isolation of the nutrient (medullary) circulation. At 4 weeks, the segment was not perfused when supplied only by the epiphyseo-metaphyseal system. It would appear, therefore, that the periosteal circulation provides a potential source of arterial supply to the diaphyseal cortex. Furthermore, an intact periosteal circulation seems to be necessary if an isolated segment of cortical bone is to continue to be adequately perfused with blood.