CT measurement of the frontal sinus - gender differences and implications for frontal cranioplasty.

OBJECTIVE

To describe frontal sinus anatomy and explore gender variations that may have significance for cranioplasty and sinus surgery.

METHODS

150 subjects who underwent maxillofacial computed tomography (CT) between 1/1/2008 and 6/11/2008 were enrolled. Frontal sinus dimensions and forehead measurements were taken at midline and at 10, 20, and 30 mm to the left and right of midline using sagittal, coronal, and axial images. The data was analyzed for significant differences between measurements made at the selected points in the frontal sinus, for left to right variations, and for gender variations.

RESULTS

Mean anterior table thickness ranged from 2.6 to 4.1 mm and was thinnest at 10 mm left and right of midline (2.9 and 2.6 mm). Mean anteroposterior depth of the frontal sinus ranged from 8.0 to 9.3 mm and did not vary significantly at any distance from midline. Frontal sinus height was greatest at midline (mean=24.5 mm) and progressively lessened at lateral distances. Mean total width at the level of the supraorbital ridge was 52.2 mm. For all measurements, no significant left to right variation was noted. Comparing the sexes, males were found to have greater dimensions in most frontal sinus measurements, though these differences were only found to be significant at or close to midline. The male forehead was marked by more acute nasofrontal angle (119.9° versus 133.5°) and a steeper posterior forehead inclination (-7.2° versus -3.5°). The glabella was wider in males (44.4 versus 33.9 mm) and more frequently protruded beyond the ideal forehead slope line (51% versus 30%).

CONCLUSIONS

Using CT imaging, forehead and frontal sinus dimensions have been described. Generally, males had larger overall frontal sinus dimensions, and this was most pronounced in the medial area of the supraorbital ridge known as the glabella.