It has been argued in recent years that angiography is no longer essential
before undertaking a carotid endarterectomy, relying solely on a carotid du
plex scan. A case is presented where an extra-cranial branch of the interna
l carotid artery was found at surgery. This unexpected finding was obviated
having obtained preoperative angiograms. anomalies of the internal carotid
artery are reviewed.