The vertebral artery originates in mule from the subclavian artery and detaches Rr. dorsales, ventrales, laterales and Rr. spinales. The segmental dorsal branches distribute in the dorsolateral muscles of the neck, while the ventral branches share in the formation of the plexus arteriosus vertebralis externus ventralis. Each spinal branch gives off R. canalis vertebralis and continues as A. nervomedullaris.
Each nervomedullary artery divides into A. radicularis dorsalis and A. radicularis ventralis. The dorsal radicular arteries share in the forma tion of A. spinalis dorsolateralis, while the A. spinalis ventralis originates from the right and left Rr. radiculares ventrales l.