Rotational movements in the territory of vertebrobasilar artery of the head and 
neck can induce vertebrobasilar insufficiency (VBI) or infarction. The term "bow 
hunter's stroke" or "rotational VBI" has been used to describe this clinical 
syndrome. In most cases, symptoms were provoked because of involvement of a 
dominant vertebral artery (VA) with hypoplasia or occlusion of the contralateral 
VA. The author presented a case in which bow hunter's stroke was caused by 
occlusion of a non-dominant VA ending in the posterior inferior cerebellar 
artery (PICA). Diagnosis of rotational VBI was based on stereotypical clinical 
symptoms related to head rotation and hemodynamic study of the effects of head 
rotation. VA compression was documented in dynamic ultrasonography including the 
disappearance of end-diastolic flow in extracranial portion of VA and marked 
reduction in blood flow velocity (more than 50%) in the intracranial portion of 
VA upon head rotation. We emphasize that rotational occlusion of this anatomical 
variation is an important cause of VBI. This may cause permanent neurological 
deficits if left undiagnosed.