Arterial communications between the carotid and vertebrobasilar systems include all EXCEPT

(D) Spinal artery # Arterial communications between the carotid and vertebrobasilar systems in the fetus may occasionally persist in the adult. Superior hypophysial artery is an artery supplying the pars tuberalis, the infundibulum of the pituitary gland, and the median eminence. It is a branch of the posterior communicating artery which branches from the internal carotid artery in the circle of Willis. Primitive trigeminal artery is the most cephalad and common of these persistent fetal anastomoses. Persistent trigeminal artery usually arises from the presellar ICA as it exits the carotid canal and enters the cavernous sinus and it extends posteriorly to join the distal third of the basilar artery usually between the origins of the superior and anterior inferior cerebellar arteries.