HISTOLOGICAL VARIATIONS IN VARIOUS SEGMENTS OF VERTEBRAL ARTERY

Compromise of vertebrobasilar circulation results in ischaemia of brainstem and cerebellar structures. Vertebral Artery (VA) follows a unique, long and tortuous course through the neck and cranium. It is divisible into 4 distinct parts. This seems to be the nature's way to allow for the movements of neck without altering the blood supply to the vital organs. MATERIAL AND METHODS VA were dissected in cadavers throughout its length on both the sides and the following segments V1: part (Proximal, Distal), V2: part, V3: part, and V4: part (Proximal, Distal) were removed. Tissues were processed and were stained with hematoxylin and eosin, Orcein and Masson's trichrome stains. RESULT AND CONCLUSION A higher incidence of thickening of SET showed variability in the thickness. Wavy character, straight outline or at places interruption IEL is suggestive of patchy atherosclerosis in the vessel which may lead to the narrowing of the lumen and during pressure or stretching due to rotational movement may compromise the blood supply leading to vertebrobasilar syndrome. In some vessels presence of a thrombus with an attempt to canalization indicates that if there is no efficient collateral circulation the areas supplied may suffer from ischaemia.