Terminal triplication of the left vertebral artery: a unique variation.

This report describes a unique case of triplication of the terminal left vertebral artery, forming the basilar artery in a 75-year-old male. CT angiography of cranio-cervical vessels also demonstrated the right vertebral artery originating from the right common carotid and an aberrant right subclavian artery.To the best of our knowledge this is the first report of a variation of this nature. The embryology and the clinical importance are discussed.