Common Cervical and Cerebral Vascular Variants.

Successful open and endovascular carotid artery intervention depends on a thorough foundational knowledge of cervical and intracranial vascular anatomy. It is essential for the carotid interventionist to be familiar with the common and rare variants of the cervical and intracranial vasculature, and to understand the implications of these variants for the performance of carotid intervention with protection of the distal circulation. This article provides interventionists with a basic description of the normal and relevant variant vascular anatomy from the aortic arch to the circle of Willis, and outlines the potential difficulties that specific variants may present for endovascular therapy.