Variant termination of the common carotid artery: cases of quadrifurcation and pentafurcation

Abstract

Knowledge of variant termination of common carotid artery is important to prevent inadvertent vascular injury during surgical, interventional and diagnostic radiological neck procedures. The variations show population differences but there are scanty data from the black African populations. Further, though trifurcations have been reported, quadrifurcations and pentafurcations are hitherto undocumented. This study therefore examined the pattern of termination of 208 left common carotid arteries in the black Kenyan population by cadaveric dissection at the Department of Human Anatomy, University of Nairobi. The conventional bifurcation into internal and external carotid arteries occurred in only 128 (61.5%) of cases. Trifurcation occurred in 66 (31.7%), quadrifurcation in 11(5.4%) and pentafurcation in 3 (1.4%). In all cases of trifurcation, superior thyroid artery was the third branch. The common carotid artery quadrifurcated into external, internal carotid, superior thyroid and ascending pharyngeal arteries. The pentafurcations comprised internal carotid, external carotid, superior thyroid, occipital and posterior curricular arteries. These findings imply that the black Kenyan population has over 38% frequency of variant termination of common carotid arteries comprising trifurcation, quadrifurcation and pentafurcation which may complicate radical neck dissection, vascular surgery, carotid catheterization and selective embolization. Surgeons and radiologists should approach the common carotid bifurcation with extra caution.