The aim of the study was to determine the heights of the anterior skull base and the distances between the anterior nasal spine and the skull base at three levels by means of coronal and reformatted sagittal images of computed tomography. The present study was performed on coronal and reformatted sagittal CT scans of 30 patients with sinonasal complaints. On the coronal view, the heights of the cribriform plate, the roof of ethmoid, and lateral lamella and the medial take-off angle between the ethmoid roof and cribriform plate were measured at different levels. On the reformatted sagittal images the distances from the nasal spine to the anterior cranial base at three different levels were measured. Then, the side-to-side variability of these measurements was statistically compared. The variations with normal distribution and abnormal distribution were analysed by paired t test and Wilcoxon paired-signed rank test, respectively. A statistically significant difference was detected only between the right and left sides in the height of the lateral lamella at the crista galli level (p < 0.05). The lateral lamella at the crista galli level on the left side was higher than on the right side. No statistically significant differences between the left and the right sides were noted in the heights and the distances of other data (p > 0.05). The normal anatomy of the anterior skull base has been described in detail on coronal and reconstructed sagittal computed tomography. These measurements may be helpful in the presurgical evaluation of patients undergoing endoscopic sinus surgery to optimize surgical safety.