Review of vertebral artery fenestration and novel extracranial fenestration

Abstract

Although anomalies of the vasculature of the head and neck are ot particularly common, vertebral artery abnormalities have been ell described in the literature. Anatomical variations of the verebral arteries can pose significant risk for vascular injury during urgical and endovascular interventions [1]. Therefore it is imporant to understand and recognize these anomalies. The classic anatomic course of the vertebral artery has its oriin from the subclavian or innominate artery, enters the foramen ransversarium of C6–C2 where it courses around C1 to enter the oramen magnum and join the contralateral vertebral forming the asilar artery. There are some important variations of the usual natomy. The vertebral artery enters at the C6 foramen in 93% of atients; alternatively, the vertebral artery may enter at C4, C5, or 7 at the respective frequency of 1, 5, and 0.8% [1]. An aberrant verebral artery course may lead to iatrogenic injury during surgical pproaches to the cervical spine. Understandably, it has been proosed that the course of the vertebral artery should be noted in the nterpretation of all routine cervical spine MRIs. In addition to an berrant arterial route, various authors have previously described everal anomalous origins. The vessel itself may randomly divide nd reconstitute as seen in arterial fenestrations and duplications.