The authors summarize in the submitted paper the basic findings on sonography and its application in otolaryngology in examinations of the paranasal sinuses. They present also findings on the physical principles of sonography needed for correct implementation and evaluation of sonographic findings of A mode sonography of the paranasal sinuses. The authors submit recommendations for the basic clinical classification of findings of A-mode sonography of the paranasal sinuses in three basic categories. A-mode sonography of the paranasal sinuses is a method which they recommend for clinical practice. The main advantages of sonography of the paranasal sinuses is the diagnosis of acute inflammations of the paranasal sinuses with minimal burdening of the patient and the possibility to follow-up the course of treatment in acute inflammations. In children above three years and in pregnant women A mode sonography is according to the authors the method of choice. Other advantages of the method are low cost and adequate accuracy of the findings in particular for the diagnosis of acute inflammations of the paranasal sinuses. The authors also draw attention to the pitfalls of the A mode sonographic diagnosis in the area of paranasal sinuses. They mention in particular that it does not replace X-ray examination (in particular CT) and that it is not a method for detection of tumours of the paranasal sinuses. Disagreement between the clinical picture and the finding on A mode sonography is an indication for further diagnostic procedures. If the examination is correctly performed and its results are correctly and critically evaluated the examination is diagnostically reliable.

        Key words: sonography amplitude modulate, basic principles of sonography, classification of sonographic findings.