Introduction. Computed tomography is a non-invasive technique for examining patients and is helps to study the structures of the paranasal sinuses before endonasal interventions. The purpose of the study: to develop the criteria for assessing the architectonics of the ethmoid bone using computed tomography to determine the anatomical and topographic features of its structure, for endonasal surgical treatment planning. Tasks: to study variants of the anatomical structure of the nasal cavity, ethmoid bone, using the method of x-ray computed tomography and determine their role in planning tactics of endonasal surgical interventions. Materials and methods: 130 patients were examined, two groups of patients were formed — the first 65 people with cerebrospinal fluid lick, and the other 65 people with inflammatory diseases of the paranasal sinuses. All the patients underwent computed tomography, after which we studied the anatomical structure of the ethmoid plate of the ethmoid bone and cells of the ethmoid labyrinth and the contents of the paranasal sinuses were evaluated. Research results. The study revealed 6 basic anatomical and topographic types of the structure of the ethmoid bone. We evaluating the position of the plane of the ethmoid plate, a conclusion was made about the location of the roof of the nasal cavity: high, medium or low. The deeper the olfactory fossa is, the lower the general nasal passage is. Conclusions. The revealed low location of the roof of the nasal cavity was regarded as a predisposing factor to the development of iatrogenic cerebrospinal fluid lick with endoscopic endonasal intervention.