Unilateral thyrovertebral trunk: report of a rare arterial variant.

Atypical origins of the vertebral and the inferior thyroid arteries are rare anatomical findings. We present the case of a right-sided thyrovertebral trunk observed in a 91-year-old female cadaver. In this extremely rare vascular variation both the vertebral and the inferior thyroid arteries jointly originated from the subclavian artery as its first branch by forming a short trunk. A thyrocervical trunk was absent resulting in anomalous origins of most subclavian branches. The vertebral artery travelled cranially entering the transverse foramen of the fifth cervical vertebrae. We furthermore discuss the clinical significance of this variation in the context of surgical and interventional procedures performed in the lateral neck region.