Abstract
PURPOSE: Angiographic techniques have gained increasing importance in suspected vascular disease of the spinal cord. This demands an advanced understanding of spinal cord blood vessel anatomy and its embryologically founded broad spectrum of variations. The aim of this study was to improve knowledge on contentious issues concerning the development of spinal cord arterial supply in higher mammals and to offer visual information of high didactic value. METHODS: The prenatal development was examined in cattle, using multiplanar high-resolution microangiography of injected specimens and microscopic sections. The gestational ages of the 15 specimens were between the late embryonic and the early fetal period (5-11 weeks). Microangiography of the human spinal cord from an earlier published study were used to envisage an adult arterial vascularization pattern in higher mammals. RESULTS: Establishment of the unpaired anterior spinal artery (ASA) goes through two procedures of reconfiguration until achieving its final design. Regression of the primarily established anteromedian tract is observed in cattle fetuses of 9-10 weeks. Return to the ontogenetic disposition of bilateral symmetry and a burst of vascularization from all parts of the spinal meninges follow and include the anterior median fissure as a preferred vascular pathway. Large sulcal/central arteries longitudinally anastomosing between each other emerge on both sides of the midline. The embryological pattern of exclusive peripheral medullary supply must have been converted into a combined system of predominant central (centrifugal) supply of the enlargements before a final unpaired ASA can be reconstructed. CONCLUSION: Previous investigators focused on the early embryonic development of spinal cord arteries and missed the profound remodeling of the vascular architecture in the early fetal period.