Positional Variations of the External and the Internal Carotid Artery

Introduction: clinical examination and surgical procedures require the knowledge of anatomical peculiarities of a complex area such as neck, especially if the anomalies in develoment of vascular system may occur. Aim: to investigate the mutual relation of the initial parts of the internal carotid artery and the external carotid artery, as well as the height of crossing of these blood vessels. Patients and methods: we evaluated 50 patients referred to diagnostic center of the PZU „Medicom“ Zenica, by using of magnetic resonance imaging (MRI) of the neck. Results: External carotid artery is placed medially and goes to the frontal side of the internal carotid artery in 90% cases. In 7% of cases the right internal carotid artery is placed laterall from the internal carotid artery. Divergent position, where the internal carotid artery (medially) and the external carotid artery go away from each other, was found in 1% of cases. We also found that the internal carotid artery and external carotid artery cross approximately 3.04 cm above the bifurcation (at right 3.05 cm and at left 3.12 cm) and the height of the crossing varies from 1.3 cm to 4.2 cm (at right 1.3 cm to 4.2 cm, and at left 1.5 cm to 4.1 cm). The height of crossing is symmetric in 18% of cases. Reversal of the position of the external and internal carotid arteries was found in 7% cases. Conclusion: The possibility of an inversed disposition of the internal and external carotid arteries must be held in mind when performing arterial ligatures in the carotid triangle, to avoid damage to the internal carotid artery or haemorrhagic accidents.