Metabolic pathways of the fossil dinosaur bones. Part I. Vascular communication system.
The fossil dinosaur bones over 80 million years old were studied. Samples for examination were prepared with specially elaborated methods. Observations in the light and scanning electron microscope yielded images of the spatial distribution of vascular canals. Besides, the contents of these canals were isolated; the contents fully corresponded to the vascular network in dinosaur bones under study, this permitted the morphological assessment of the vascular system. In the dinosaur bone, independently of its type, i.e. whether it was primitive e.g. plexiform, or Haversian , two blood inflow tracts were distinguished: the main, primary tract running from the marrow cavity, and the secondary tract departing from the periosteum. Examinations made with the use of an X-ray microanalyzer corroborated the essential importance of the tract running from the marrow cavity, revealing the presence of the same material (iron) in the wall of the marrow cavity and in the vascular canals closely connected with this part of the cavity. The bone was found to contain the axial vascular canals, whose course was parallel to the long axis of the bone, and the anastomosing canals perpendicular to them and thereby to the long axis of the bone. The system of the interlinked canals of the two types bounded the bone mass into a prism. The osseous space restricted by these canals was defined as the functional bone area, undoubtedly functionally subject to the control of the surrounding vessels. The spatial system of the functional bone areas was more orderly and these areas were markedly smaller in the primitive, plexiform bone than in the Haversian bone.(ABSTRACT TRUNCATED AT 250 WORDS)