The circle of Willis is not always able to maintain adequate blood supply to the hindbrain when the vertebral arteries are diseased. 7 This is illustrated in Case 3, in which the only demonstrable ...

[9] Warfarin reduced the risk of the primary end point among patients with basilar artery stenosis ... and posterior circulation and the circle of Willis should be defined with a diagnostic ...

The right subclavian artery is occluded at its origin (a ... and posterior circulations of the brain through the circle of Willis. These 2 factors are essential for appreciation of the hemodynamic ...