Dimensions of Velopharyngeal Space following Maxillary Advancement with Le Fort I Osteotomy Compared to Zisser Segmental Osteotomy: A Cephalometric Study

Figure 1

Variables used for cephalometric evaluations: points: ANS, most anterior point of anterior nasal spine; PNS, posterior nasal spine; PPW, posterior pharyngeal wall; U, tip of the uvula; S, midpoint of hypophyseal fossa; N, most anterior point of frontonasal suture. Planes: SN, sella-nasion plane; PP, palatal plane. Distances: PNS-PPW, distance measured parallel to the PP from PNS to PPW; PNS-PPW90, distance measured with line drawn perpendicular from PNS to PPW90; U-PPW′, distance measured parallel to the PP from U to PPW′; U-PPW90′, distance measured with line drawn perpendicular from U to PPW90′; ANS-PNS, distance measured ANS to PNS (for the maxillary dental arch length); PNS-U, distance measured from PNS to U; ANS-SN, distance measured with line drawn perpendicular from ANS to SN; PNS-SN, distance measured with line drawn perpendicular from PNS to SN. Angle: SN-PP, angle between SN and PP. Area: area of the airway located above the line drawn parallel to the PP and passing through U point.