The posterior cerebral cortex receives vascular supply from the vertebral-basilar system of arteries. This system begins with the vertebral arteries bilaterally, which arise from the subclavian arteries and ascend through the foramen transversarium of the cervical vertebrae in the neck. After entering the foramen magnum at the level of the pontomedullary junction, the arteries join to form the basilar artery, which courses along the midline of the ventral brainstem (eFig. 9.20). At the level of the midbrain, the basilar artery gives rise to the posterior cerebral artery (PCA), which turns posteriorly and gives rise to branches that perfuse the inferior and medial temporal and occipital lobes. Also at the PCA, a connecting artery, the posterior communicating artery, branches off and connects to the internal carotid artery (eFig. 9.22).