LAUSR

Abstract The aim of this study was to elucidate the precise location of the maxillary ostium using computed tomography for the reduction of depressed nasomaxillary fractures. Computed tomography images (61 males, 42 females; age range, 3–97 years) were analyzed. Coronal sections were cut every 3 mm. The primary maxillary ostium (PMO) was located 24.7% ± 3.9% of bizygomatic distance (BZD) lateral to septum. The horizontal distance of the PMO significantly increased with age (P = 0.032). The PMO was located 53.3% ± 8.0% of nasal length (NL) above superior surface of the palatal bone (SP). The vertical-to-horizontal ratio of the PMO decreased with age (P = 0.013). The PMO was located 30.3 ± 4.3 mm posterior to the tip of nasal bone. The PMO was located 24.6 ± 4.8 mm posterior to the anterior nasal spine (ANS). The ANS-PMO distance significantly increased with age (P = 0.027). The hiatus semilunaris (HS) was located 11.9% ± 3.2% of BZD lateral to septum. The HS was located 62.4% ± 10.3% of NL above SP. The vertical distance of the HS significantly decreased with age (P = 0.019). The accessory maxillary ostium (AMO) was located 14.9% ± 2.8% of BZD lateral to septum. The horizontal distance of the AMO significantly increased with age (P = 0.027). The AMO was located 44.8% ± 6.9% of NL above SP. The vertical distance of the AMO significantly decreased with age (P < 0.001). The vertical-to-horizontal ratio of the AMO decreased with age (P < 0.001). The distances of the ostium from surgical landmarks measured in this study might be helpful when inserting a small curved elevator into the maxillary ostium in the reduction of medial maxillary fractures.