Verónica Inostroza; Paulina Araya; Sofía González; Oscar Inzunza ; Jaritza Tramolao & Emilio Farfán

There are many reports on anatomical variations of the vertebral arteries, which may be related to origin, trajectory, caliber, and side. Bilateral variations are less frequent, however, and less common are bilateral variants that differ from each other. The aim of this work was to report the presence of a bilateral variation of the vertebral artery and its functional and clinical implications. Dissection of a female cadaver, fixed in 10 % buffered formaldehyde, which had not undergone any previous surgeries in the study area and had anatomical variations in both vertebral arteries. In each one, follow-up was done from its origin to its end, determining its trajectory, diameters, branching, and anatomical relations. A left vertebral artery was found, starting in the aortic arch and making a sinuous trajectory of 4 curvatures to enter the transverse foramen of C4. The right vertebral artery began as the first branch of the subclavian artery. Its initial trajectory was rectilinear, followed by a right concave curve, a 360° loop that included a second ascending curve, and ended straight before entering the transverse foramen of C6. The coexistence of bilateral variations in the vertebral arteries is possible. This atypical situation can potentially generate vascular and neurological pathologies, but with different symptoms and causes. Knowing these variations and deliberately searching for them will enable the specialist to make a suitable differential diagnosis.

KEY WORDS: Vertebral artery; Bilateral variation; Loop; Aortic origin.

INOSTROZA, V.; ARAYA, P.; GONZÁLEZ, S.; INZUNZA, O.; TRAMOLAO, J. & FARFÁN, E. Bilateral variation of the verte- bral artery. Report of a case and its clinical implication. Int. J. Morphol., 41(3):1015-1019, 2023.