Bone regeneration in animals and in man. A contribution to understanding the relative value of animal experiments to human pathophysiology.

Under both normal and pathophysiological conditions the relationship between bony histology and the regionally associated vascular pattern was studied. Three independent methods of research were employed (microangiography, fuchsin stained ground sections, polychrome sequential labeling) and, thus, the limitations inherent in each method were minimized. Animals of different ages and different species were found to have relatively different amounts of primary and secondary bone. In all instances primary bone was associated with a network vascular pattern emanating from the periosteal surface and secondary bone was associated with an arborial vascular pattern arising from the endosteal circulation. Adult dogs, unlike sheep, were found to have a significant complement of secondary bone and, therefore, in consideration of human bony regeneration, the dog is a superior experimental model.