(Un)Common Carotid Trifurcation.

Variations in the position of the bifurcation of the common carotid artery (CCA) and the origin or branching pattern of the external carotid artery are uncommon. Variations in transformation of the embryonic aortic arch system are the genesis of these variations. A 70-year-old female presented with history of sudden onset dizziness followed by right hemiparesis showed a trifurcation of CCA on carotid duplex ultrasound (CDU) scan. Computed tomography angiography (CTA) of the extracranial neck vessels confirmed our sonological findings and it was determined that the third vessel originating from the CCA was an aberrant superior thyroid artery (STA). Knowledge of variant terminations of the CCA is important to prevent inadvertent vascular injury during radical neck dissection, cervical discectomy, and carotid artery catheterization and a CDU is a prudent screening tool for the same.