FIELD : medicine.SUBSTANCE : invention relates to medicine, particularly to otorhinolaryngology. A rigid endoscope is inserted into the nasal cavity. At the level of the anastomosis edges between the nasal cavity and the sphenoid sinus, a surgical probe is installed for an attic, the working portion of which is placed anastomosis of sphenoid sinus. A video image of the above probe is obtained and stored on a computer. Circumference of probe working part and anastomosis contour are selected. Determining their quantitative values using a program for analyzing and processing images. An anastomosis of sphenoid sinus area is determined using the claimed formula.EFFECT : method enables determining the area of the anastomosis of sphenoid sinus, providing adequate mucociliary transport and sinus drainage ensured by the significant technique of determining the area of the anastomosis of sphenoid sinus.1 cl, 4 dwg, 1 ex