Ulcers in extracranial carotid arteries are a known source of cerebral embolism. However, there are no data available on the prevalence of ulcerations located at the origin of these vessels in the aortic arch. Therefore, in this pathological study the topographic distribution of ulcerated lesions were determined in these arteries. One hundred and one consecutively autopsied patients composed the study group. Ulcerated plaques were sought for in both carotid arteries, from their origin in the arch up to the carotid canal, and also in the aortic arch and ascending aorta. The two anatomical sites mostly affected by atherosclerosis were the region of the carotid sinus and the orifices of cervical arteries in the aortic arch. More than one third of all ulcers were at the orifices of cervical arteries in the arch. Interestingly, ulcers at the orifice of the left common carotid artery in the arch were accompanied with other ulcers located elsewhere in the remaining segments of the left carotid system, whereas ulcerations at the orifice of brachiocephalic trunk were not accompanied with other concomitant lesions in the right carotid system. Furthermore, there was no symmetric distribution of ulcerated plaques in both carotid systems.