IN A clinicopathologic study of 178 cases of atherosclerosis of the vertebral and carotid arteries,1 infarction in the vertebral-basilar territory was related to occlusive disease situated intracranially. This was in contrast to the findings in infarction in the territory of the internal carotid artery in which the occlusions lay predominantly extracranially. The number of cases of infarction was small, and generalizations were unwarranted, but we were prompted to make further observations on the tolerance of the cerebral circulation to a reducion in the forward blood flow through the extracranial vertebral arteries bilaterally. Since postmortem examination fails to provide information about hemodynamics, attention has been focused on cases studied arteriographically during life, with particular regard to the pathway by which the intracranial vertebral-basilar system is supplied.
Bilateral extracranial vertebral compromise results from occlusion or stenosis of both vertebral arteries, or of one vertebral artery when the other is vestigial