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Type 1 persistent proatlantal artery (red arrow) “arising” from the external carotid artery. In reality the proatlantal artery is the occipital artery (note identical course and lack of separate proximal occipital artery in these views, with the distal occipital artery marked by the blue arrow), with the C1 muscular branch (purple arrow) reconstituting the distal VA (yellow arrow).
