Posterior circulation stroke accounts for about 20% of all ischemic strokes in a variety of syndromic pictures ranging from lacunar and limited infarcts to more extensive involvement. Furthermore, infarcts in the vertebrobasilar (VB) region are frequently multiple and not univocally identifiable in one single clinical entity; the prognosis is sometimes unpredictable and very often is unfavorable having a high early mortality rate. The basilar artery (BA), which is the main vessel of the posterior circulation, supplies most of the brainstem and occipital lobes and part of the cerebellum and thalami, its occlusion (BAO) is the most severe occurrence in the posterior circulation infarct context. The optimum management of BAO is still under debate and in the absence of randomized studies the most appropriate approach is still unclear. In the previous chapters, single territory infarcts involving the posterior circulation have been discussed. The present chapter will discuss extended infarcts in the VB territory due to different degrees of VB involvement or to BAO.