Abstract:
Bifurcation of the common carotid artery (CCA) and the branching pattern of the carotid arteries
in the neck show great anatomical variations. Better knowledge of these variations is clinically
important for surgical procedures and radiological investigations. Variant Anatomy of carotid
arteries has been reported but there is no data in Sri Lankan population. This study aimed to
evaluate the variations in the level of bifurcation of the CCA; the origin of the external carotid
artery (ECA) in relation to the internal carotid artery (ICA) and the variations in the origin of the
superior thyroid artery (STA). Twenty eight common carotid arteries of 14 cadavers were used for
the study. CCA bifurcation was classified into three groups, with reference to the level of the upper
border of the thyroid cartilage (TC). They were standard bifurcation, high bifurcation and low
bifurcation. Standard bifurcation was observed in 5 (17.9%), high bifurcation in 19 (67.9%) and
low bifurcation in 4 (14.3%). The origin of ECA was anterior to the ICA in 16 (57.1 %), and
anteromedial in 6 (21.4 %). While 19 (67.9%) of STA originated from ECA at the level of carotid
bifurcation or just above the carotid bifurcation 7 (25%) of STA arose from CCA. In one cadaver
there was no STA in both sides. In conclusion, the level of bifurcation CCA varied from above the
level of hyoid bone to the lower border of the TC. Bifurcation above the upper border of the TC
was the most frequent bifurcation level of the CCA. The ECA most commonly originated anterior
to the ICA. The knowledge of these anatomical variations is useful in surgical and clinical
investigation procedures. Therefore further studies to evaluate anatomical variations of carotid
arteries is paramount important.
