Abstract: Fundamental evolution of neuronal injury in terms of neural tissue alterations as developing in perinatal brain ischemia/hypoxia might underlie a variety of mechanisms implicating particularly a progressive form of nonperfusion of regional capillary bed blood flow. Indeed, a concept of immaturity of such regional capillary beds perfusion of the fetal/neonatal brain might help account for such progressiveness of nonperfusion that would render simple blood flow patterns of disturbance a primary mechanism in perinatal brain injury. In terms therefore of distinction between ischemia and hypoxia as arising from progressive nonperfusion of neural tissue capillary beds, one might perhaps realize systems of primary neuronal injury that would subsequently tend in certain cases to evolve in terms largely of suborganelle or mitochondrial injury. One might recognize primary and secondary order forms of neuronal and neural tissue injury in perinatal brain ischemia/hypoxia arising largely as progressive forms of nonperfusion of capillary beds that would operate essentially as degrees of such progressiveness towards further cellular and tissue injury.