Predictibility of the cervical origin of the anterior spinal artery.

SUMMARY: The anatomic study (under a surgical microscope) of 25 brains that had previously been injected with colored latex confirmed the fact that in the majority of cases, the anterior spinal artery results from the merging of two arterioles which both derive from two vertebral arteries. This bilateral nature is determined by the symmetric origin of the posterior inferior cerebellar arteries. When the conformation is asymmetrical, a single anterior spinal artery branches off from the vertebral artery that supplies the closest posterior inferior cerebellar artery.