Date Published: June 6, 2012
Publisher: Hindawi Publishing Corporation
Author(s): Aprajita Sikka, Anjali Jain.
Understanding the great vessels of the aortic arch and their variations is important for both the endovascular interventionist and the diagnostic radiologist. An understanding of the variability of the vertebral artery remains most important in angiography and surgical procedures where an incomplete knowledge of anatomy can lead to serious implications. In the present case, a bilateral variation in the origin and course of vertebral artery was observed. The left vertebral artery took origin from the arch of aorta and entered the foramen transversarium of the fourth cervical vertebra. The right vertebral artery took origin from the right subclavian artery close to its origin and entered the foramen transversarium of the third cervical vertebra. The literature on the variations of the artery is studied and its clinical significance and ontogeny is discussed.
Anatomical variation is defined as the normal flexibility in the topography and morphology of body structures . Many or most variations are totally benign; some are errors of embryologic developmental timing or persistence of normally obliterated structures .
During routine dissection of head and neck region in the dissection hall, a bilateral variation in the origin and course of vertebral artery in an adult female cadaver whose age was around 35 years was observed. The diameters of the two arteries were measured at the origin and where they entered the foramen transversaria with digital vernier calipers (in millimeters [mm]). The length of the arteries was measured with a thread and vernier calipers (in mm).
The left vertebral artery took origin directly from the arch of aorta between the left common carotid artery and the left subclavian artery. The origin was posterolateral to the left common carotid artery, just proximal and anterior to the left subclavian artery (Figure 1). The artery was tortuous, crossed the left common carotoid artery posteriorly to come, and lie on its medial side. It then ascended paravertebrally and entered the foramen transversarium of the fourth cervical vertebra (Figure 1). Thereafter, it followed the normal course to enter the cranial cavity through foramen magnum.
A thorough understanding of anomalous vertebral arteries is paramount when performing both diagnostic and interventional angiography. Contrast enhanced MRA is becoming increasingly common, and with improved resolution, identifying pathology including ostial lesions of the great vessels and vertebral arteries will become more frequent .