Variant course of the vertebral artery

We present a 69 year old female with dizziness. During the evaluation of the carotid we did not found the vertebral artery in the transverse foramina in the middle of the neck. However an  artery was traveling  side by side with carotid, in the level of the mandible this artery  turns and enters the intraspinal foramen.

Image Vas:

The right  vertebral artery  follows a parallel course  side by side with the  common carotid artery .

Image Va turn: 

At the level of the mandible the VA  turns and enters the transverse  foramen.

Image U l ob:

RIGHT oblique view: The lower segment, thefirst part, of the  vertebral artery

LEFT transverse view: The upper  segment of the  extraspinal vertebral artery before to  enter the transverse foramen.

TRA  RCC RVA

RIGHT transverse view:    The extraspinal  vertebral artery before to  enter  the transverse foramen and the common carotid artery .

LEFT transverse view:   the bifurcation of the common carotid artery .

Discussion by Dr Nikos Vougiouklis

The vertebral arteries may present in a number of variant positions. The presence of a vertebral variant must be considered in patients in whom the normal position of the vertebral artery cannot be detected. The vertebral arteries enter the 6th cervical foramen in most cases.

 In cases in which the vertebral artery enters  of the higher vertebral foramina, the artery may lie directly behind the common carotid artery. In a study by Bergman et al based on 693 laboratory specimens, dual or accessory vertebral arteries were encountered in 5 of 693 specimens, and all were left-sided.

References:

1. Koenigsberg RA, Peereira L, Nair B, et al. Unusual vertebral artery origins: examples and related pathology. Catheter CardiovascInterv 2003;59:244–5
2. Bergman RA, et al. Opus II: cardiovascular system vertebral artery variations. In: Bergman RA, Afifi AF, Miyauchi R, eds. Illustrated Encyclopedia of Human Anatomic Variation.