Extracranial Segments of the Vertebral Artery: Insight in the Developmental Changes up to the 21st Year of Life.

The vertebral artery (VA) bilaterally arises usually from the subclavian artery and courses within the bony canals of cervical vertebrae, and then it reverses directions on the first vertebra before piercing the dura to enter the cranium.The aim was to follow (ab)normal developmental changes of extracranial VA from prenatal status to age 21. This chapter included a brief description of the arterial embryology and morphofunctional specificity of the VA in prevertebral, cervical, and atlantic parts, during prenatal and postnatal period.The authors concluded that the subclavian origin of the VA was in most of fetal and adult cases. The incidences of variable VA origins and domination of one of the VAs were different from one series of human specimens to the second one. Although in most of cases, anomalous origin and/or variable course of the extracranial VA had little or did not result in clinical symptoms in infants and young adults, the true value of their discovery is in the diagnostic gain before vascular surgery of supra-aortic arteries.