External Carotid Artery Variations: A Case Series Highlighting Clinical and Surgical Importance and Embryological Basis

Abstract This case series presents four uncommon vascular anomalies of the carotid arterial system identified during routine cadaveric dissections. We describe atypical spatial arrangements between the internal carotid artery (ICA) and external carotid artery (ECA), including instances where the ICA is positioned medially relative to the ECA, and pronounced ECA curvature forming a 6.2 cm S-shaped loop. In addition, two rare branching configurations were noted: a linguofacial-laryngeal trunk giving rise to the lingual, facial, and superior laryngeal arteries, and an ascending pharyngeal-occipital trunk. These findings were observed in cadavers aged 65–72 years. The observed vascular irregularities have significant implications for head-and-neck surgeries, such as thyroidectomy, laryngectomy, and carotid endarterectomy, as well as for radiological assessments and interventional techniques. We explore the developmental origins of these anomalies, likely stemming from irregular vascular migration during embryogenesis. This series emphasizes the importance of clinicians recognizing potential carotid artery deviations to prevent procedural complications and optimize patient outcomes. By thoroughly documenting these cases, we contribute to the expanding knowledge base on vascular anomalies and their clinical significance.