Radiological correlation between the anterior ethmoidal artery and the supraorbital ethmoid cell

The anterior ethmoidal artery is an important landmark in functional endoscopic sinus surgery. We undertook this study to determine the reliability of identification of the artery on the coronal CT scan and to determine whether a correlation exists between the pneumatisation of the suprabullar recess and the vertical distance of the artery from the base skull. 50 randomly selected CT scans were studied. The anterior ethmoidal artery was identified on each side and the vertical distance between the artery and the base skull was measured. The orbital beak and the superior oblique muscle were used as landmarks to identify the artery. The CT scans were divided into two groups based on whether the supraorbital cell was present or absent. These groups were each further subdivided into 3 groups depending on the vertical distance between the anterior ethmoidal artery and the base skull. The anterior ethmoidal artery was reliably identified in 97% of the cases. When the supraorbital cell was absent, the mean distance between the artery and the base skull was 1.5 mm; while when the cell was present, the mean distance was 4.86 mm. When these groups were evaluated for statistical significance, the p value was 0.000 (highly significant). The orbital beak and superior oblique muscle are reliable landmarks to identify the anterior ethmoidal artery. There exists a strong correlation between the vertical distance of the artery from the base skull and the presence of the supraorbital ethmoid cell.