Abstract
BACKGROUND: The tortuosity of the cervical segment of the internal carotid artery (c-ICA) holds clinical and surgical significance, yet its associated anatomical factors remain insufficiently elucidated. This study aimed to explore the incidence of c-ICA tortuosity in cadaveric specimens and assess its correlation with macroscopic and microscopic parameters pertaining to the c-ICA. METHODS: The study involved dissection of the c-ICA in 52 cadaveric specimens, with documentation of tortuosity type, the level of common carotid artery (CCA) division, carotid sinus (CS) morphology and location, anatomical relationships of the c-ICA, and circumferences of the CCA and c-ICA. Additionally, 20 specimens were processed for haematoxylin and eosin staining and confocal microscopy for vessel wall evaluation. RESULTS: Of the 52 specimens (N = 52), 30 (57.69%) exhibited c-ICA tortuosity, predominantly C- and S-shaped tortuosity (t-C&S, 63.33%), followed by kinking (25.67%) and coiling (10%). Most tortuosity occurred in the proximal segment (76.66%), with fewer instances in the distal segment (6.67%) or both segments (16.67%). c-ICA tortuosity exhibited no association with laterality, the level of CCA division, CS morphology, or CS location. Notably, the c-ICA's course relative to the superior cervical ganglion (SCG) played a significant role, with the majority of tortuosity originating at the lower pole of the SCG (96.67%). Specimens with tortuosity showed significantly greater circumferences of both CCA and c-ICA, in the order of coiling, kinking, and t-C&S. Microscopic analysis revealed a thicker tunica intima and more prominent internal elastic lamina in t-C&S and kinking specimens, with disorganisation in the tunica media across all tortuosity types, more so in coiling. CONCLUSION: Factors such as level of CCA division, CS morphology, and location do not appear to influence c-ICA tortuosity. Vessel wall morphology, vessel wall remodelling, and anatomical relationships, particularly the SCG, contribute to c-ICA tortuosity, particularly t-C&S and kinking types. Kinking follows t-C&S in pathogenesis. Coiling exhibits distinct characteristics compared to the other tortuosity types suggesting a different underlying aetiopathogenesis.