The poor accessibility of the sphenoidal sinus for the surgeon, its peculiar topographic features, and the anatomical relationships with the structures of the brain taken together with the variety of individual variants of these structures are of great practical importance for otorhinolaryngologists, neurosurgeons, maxillofacial surgeons, and specialists in the field of radiation diagnostics. Aim. The objective of the present study was to obtain the new data on the relationship between the lateral walls of the sphenoidal sinus and the internal carotid artery. Materials and methods. The study was carried out based on the materials obtained during magnetic resonance imaging in 136 patients exhibiting no pathological changes in the sellar region. Measurements of the craniological parameters for the characteristic of the shape of the skull and the distance between the side walls of the sphenoidal sinus and the internal carotid artery were performed with the use of the «Philips DICOM Viewer R 2.4» and the 3D Doctor programs. The patients were allocated to different groups according to their gender, the shape of the skull, and age. The anatometric parameters thus obtained were processed by making use of the EXCEL and Statistica 6.1 programs. To describe the average values, the median was calculated, and quartiles (Me (Q25—Q75)) were used to characterize the variety of the traits. The statistical significance of the differences between the groups was determined by the criteria of Mann—Whitney and Kraskel—Wallis. Results. The comparative analysis of the data obtained from the patients of all study groups based on the Mann—Whitney and Kraskel—Wallis criteria has demonstrated that their values were greater than 0.05. Therefore, these results do not allow to conclude that there are statistically significant differences in the distance between the inner surface of the sinus side wall and the inner carotid arteries in the studied groups. The data obtained indicate a small variability in the distance from the inner surface of the sinus lateral walls to the internal carotid artery on both the right and left sides; moreover, they broaden the concept of the topographic and anatomical structure of the sphenoidal sinus and increase the possibilities for the surgical interventions on the sinus itself and on the neighboring anatomical structures with the use of the trans-nasosphenoidal access. Conclusion. The absence of the statistically significant differences in the distance between the inner surface of the sinus side wall and the inner carotid arteries should be taken into consideration in the interpretation of the results of magnetic resonance imaging and the performance of surgical interventions on the sphenoidal sinus and the adjacent anatomical structures making use of the trans-nasosphenoidal access.