A rare anatomic variant: the lateral position of the external carotid artery

During educational dissections a rare anatomic variant was encountered at the level of the right carotid triangle of a human adult male specimen. The variant was unilateral. On that side the common carotid artery bifurcated slightly above the level of the upper border of the thyroid cartilage, but the external carotid artery was posterolateral to the internal carotid artery and the anterior branches of the external carotid artery (superior thyroid, lingual and facial arteries) initially crossed over the internal carotid artery before continuing with a normal anatomical course. 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.