Anatomical Variations of the Frontal Sinus by CT-Scan

Introduction: The sinuses are a system of connected hollow cavities in the face that contain air and a thin layer of mucus. Paranasal sinuses are a group of four pair aerated cavities that surround the nasal cavity. They are connected to the nose by small openings. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the sphenoidal sinuses are behind the eyes. Frontal sinuses are rarely symmetrical and the septum between them frequently deviates to one or other side of the middle line. Their average measurements are as follows: height 28 mm, breadth 24 mm, depth 20 mm, creating a space of 6-7 ml. The frontal sinuses are absent at birth, but are generally well developed, and functional between the sixth and eighth years, though they continue to grow slower until reaching their maximum size after puberty. Through its copious mucus production, the sinus is an essential part of the immune defense/air filtration carried out by the nose. Objectives: Finding the average volume of the frontal sinus. Finding the difference in frontal sinus volume according to age, gender and side (right and left). Method&Material: This is a descriptive cross-sectional study which performed from 24/July/2019 to 06/August/2019 on the patients who are needed CT-scan examinations for their skull related problems to the radiology department of French medical institute for mother and children (FMIC) hospital in Kabul city. During that period of time, radiological caliches of 60 patients were studied. Radiological caliches obtained with a thickness of 0.75 mm in axial and coronal planes. Anatomical changes of the frontal sinus were studied for both sexes; it means 30 men and 30 women. The anterior, posterior, horizontal and vertical diameters of the sinuses in both right and left sides were measured in collaboration with the radiologist and inserted into dataset then analyzed. The volume is determined by the following formula according radiologist in CT-Scan. Results: The referred patients were 60 which from them 30 are men and 30 women. The minimum age of patients were 16 years old and the maximum age of patients were 65 years old, and the average age was 37.2 years old. The average volumes of the frontal sinuses for both sexes were estimated to 4.42 cm3. The average volume of the frontal sinuses near men were estimated to 4.13 cm3 and in women 4.71cm3, which indicates the larger size of the frontal sinus in women than men. The average volume of the left and right frontal sinus in women were estimated to 4.85 cm3 and 4.57cm3, which shows the larger size of the left frontal sinus in women, but it is not statistically significant. The average volume of the left and right frontal sinus in men were estimated 4.11 cm3 and 4.14 cm3, which shows the larger size of the right side sinus than left, but is not statistically significant. The minimum volume of the right frontal sinus is (0) zero, its maximum volume is 15.14 and their standard deviation is 3.25 cm3. Also, the minimum volume of the left frontal sinus was zero (0) and its maximum was 32.4 and its standard deviation was 5.1 cubic centimeters and it showed the larger frontal sinus in women. In 6.6% cases of the frontal sinuses were absent near referred patients. Conclusion: In this study, the average ages of patients were estimated 37.2 years old and the average frontal sinus volume was estimated 4.4 cubic centimeters. The volume of the frontal sinuses discovered larger in women than men. Left frontal sinus volume was larger than right one and in 6.6% of cases the frontal sinus was absent near referred patients.