Background: The segments of cerebral basal arterial network (CBAN) dampen the peak systolic pressure in blood flowing through these arteries. The number of aneurysms occurring in segments of CBAN will vary with the ability of each arterial segment to dampen the peak systolic pressure. Materials and Methods: Diameters of segments of CBAN were measured in cerebral computed tomography angiography images of 145 patients and the relative size of each vessel was calculated to standardise for differences in overall arterial sizes among patients. Relationships among sizes of CBAN components were statistically analysed. Presence of aneurysms in parts of internal carotid artery (ICA), middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery (PCA), and vertebrobasilar (VB) arteries was recorded. Results: Forty-six aneurysms in right ICA and MCA and 32 aneurysms in left ICA and MCA segments were noted in 42 and 30 patients, respectively. Aneurysms in anterior communicating artery complex (AcomAC) and VB arterial segments were seen in 27 and 8 patients respectively, while they were not detected in parts of PCA. The significant (p<0·0001) inverse relationships between sizes of posterior communicating artery (PcomA) and the first segment of PCA on both sides indicated that blood inputs to the second part of PCA were similar. This smoothens vessels haemodynamics. Differences in means of the index of arterial size variation for people with aneurysms (0·96) and without aneurysms (0·86) was significant (p≤0·015). Aneurysms in ACA, PCA and VB arteries were less and was proposed that it is due to dampening of peak systolic blood pressures. The development of aneurysms occurring in CBAN depended on the degree of variation and asymmetry in its segments. Conclusion: Variation in segments of CBAN has been quantified. The peak pressure dampening mechanism in such arterial segments reduces the chances of development of aneurysms. Funding: None to declare Declaration of Interest: There is no conflict of interest with any of the authors. Ethical Approval: Randomly selected CCTA images of 145 patients archived in the Carestream data registry system at Royal Adelaide Hospital (RAH), South Australia between January 2011 and December 2019, were used in the study (male = 67, female = 78, mean age = 60·9 years) (Supplementary file 1). Human Research Ethics Board granted permission (approval number: H2014 -176) to access and use data from the Carestream data registry system (Vue RIS version 11·0·14·35).