The aim of this study was to examine the course of the carotid artery (CA) and define CA anomalies important for neck surgery using conventional and three-dimensional computer tomography (3D CT). This was designed as an observational study with retrospective CT and 3D CT angiography analysis. 4,000 CAs depicted on 2,000 CT angiographies were analyzed to determine the relationship of common, internal, and external portions of the CA to the neck organs, with special emphasis on the thyroid gland area and organs involved in the neck dissection surgery. A total of 47 out of 4,000 imaged CAs had congenital anomalies (1.18%). These anomalies were found in 45 patients, unilaterally in 33 and bilaterally in two. The level of the common CA bifurcation to internal and external CAs was rarely abnormal. It was at the level of C5 and C6 in two cases only (0.05%). The common CA, either aberrant or tortuous, ran abnormally close to the thyroid gland in 22 cases (0.55%). In planning neck dissection surgery, laryngectomy, or thyroidectomy, the surgeon should bear in mind that CA anomalies are present in approximately 1.2% of cases. Preoperative conventional CT angiography or 3D CT allows precise identification of anomalous CAs, thereby reducing the possible risk of intraoperative injury.