Fenestration and duplicate origin of the left vertebral artery in angiography

Three cases are shown; 2 of angiographically proven distal fenestration of the left vertebral artery and one of duplicate origin. Both anomalies are classified as of inhibitory type. Their incidence in the literature is reviewed. Underlined is the fact that variations of this nature frequently occur in combination with other inhibitory malformations particularly in the vascular and skeletal systems.