Fig. 1.

Landmarks and reference planes. S, sella; N, nasion; ANS, anterior nasal spine; PNS, posterior nasal spine; U6, mesial cusp tip of maxillary first molar; U1, incisal edge of maxillary incisor; L1, incisal edge of mandibular incisor; Li, labrale inferius the most anterior point of lower lip; Pg, hard tissue pogonion; Pg′, soft tissue pogonion; Me, hard tissue menton; Me′, soft tissue menton; HRL, horizontal reference line; VRL, vertical reference line; PP, palatal plane; 1, overbite measured along VRL; 2, overjet measured along HRL