During the third to fifth week of intrauterine life the internal carotid artery develops from the proximal portion of the third aortic arch and from the cranial portion of the dorsal aorta. Alterations in its development give rise to three entities: Hypoplasia, aplasia and agenesis. A case of bilateral agenesis of the internal carotid artery is presented in a 24-year-old patient who underwent an angiotomography in the Imaging Service of the Pasteur Hospital, Montevideo, Uruguay. Anatomo-clinical implications are discussed.
