ABSTRACT:

The vertebral artery (VA) usually arises from the first part of the subclavian artery. During routine dissection of an elderly female cadaver the VA was seen to arise from the dorsal aspect of the thyrocervical trunk at the bifurcation of inferior thyroid and ascending cervical artery on the right side. It was subsequently identified to enter the foramen transversarium of the fifth cervical vertebrae. The left VA arose from the first part of subclavian artery, coursed with moderate tortuosity and showed the presence of an unusual stenosed segment. The length of the first part of the VA was noted to be 19.2 mm on the right side and 31.5 mm on the left side. The external diameter of on the right and left side was 1.8mm and 5.38 mm respectively. Previous studies have shown that it is rare for the right VA to arise from the thyrocervical trunk. The origin of VA is clinically important for vascular surgery in the head and neck as well as in the interpretation of four vessel angiography for endovascular interventional procedures and diagnostic radiology.

Keywords: Vertebral artery, Variations, Thyrocervical trunk