A Right Accessory Vertebral Artery and Variation in the Origin and its Entry to the Transverse Foramen

Abstract

Variations of the vertebral artery origin are congenital abnormalities that occur during embryonic development. The vertebral artery origins from the superior part of the first part of the subclavian artery and it provides the main blood supply of the posterior cranial fossa structures. Several variations in the vertebral artery origin and its entry to the transverse foramen have been reported in advance. However, mention to the variation of the right vertebral artery origin and its entrance to the transverse foramen is rare. By describing dissection of an old man cadaver, two vertebral arteries were observed which were arised from the first part of the subclavian artery at the right side, and they follow a different direction to enter the transverse foramen. One of the arteries rises in its natural direction and enters into the transverse foramen of C6, and the other arteries take an abnormal direction upwards and then enter the higher level surface into the transverse foramen of C4. It is necessary to mention, the artery on the left was in its normal state. Regarding neck root surgery, knowing these variations reduces arterial injury during surgery and angiography.