Tan Q, Qin C, Yang J, et al. - Researchers conducted this retrospective analysis to obtain normal ranges for the inner diameters of the carotid arteries. Between March 2013 and March 2018, patients with disease-free carotid arteries who had undergone 3D-DSA at two hospitals in Nanning, Guangxi were analyzed. The sample consisted of 1,182 hospitalized patients (837 males, 70.81%). On the right, the inner diameters of the proximal carotid sinus (CS), CS bulge, distal CS, and common carotid artery (CCA) were larger than on the left. Males had larger inner diameters of the proximal CS, CS bulge, distal CS, and CCA on both sides than females. Patients aged > 65 years had smaller inner diameters of the proximal CS, CS bulge, and distal CS on both sides than patients aged ≤ 55 years. Right CCA inner diameter did not differ with age, while left CCA inner diameter was larger for patients aged > 55 years than for patients aged ≤ 45 years. Patients with Essen Stroke Risk Score (ESRS) ≥ 3 had smaller inner diameters of the proximal CS, CS bulge, and distal CS on both sides than those with ESRS < 3. This investigation gives reference values for the internal diameters of normal carotid arteries. Carotid artery diameters varied according to side, gender, and age.