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Table 2 Landmarks and reference planes used in this study

From: Changes of lip morphology following mandibular setback surgery using 3D cone-beam computed tomography images

  Definition
Reference landmark  
 Subnasale (Sn) The midpoint of the angle at the columella base where the lower border of the nasal septum and the surface of the upper lip meet
 Labrale superius (Ls) The midpoint of the upper vermilion line
 Cupid bow point (CBP) The most elevated point of the philtrum on the upper vermilion border line
 Labrale inferius (Li) The midpoint of the lower vermilion line
 Lower lip bow point (LLBP) The breakpoint on the lower vermilion border line
 Stomion (Stm) The point at the midline of labial fissure between gently closed lips
 Rt. Lt Stomion (Stm) The breakpoint on the labial fissure line between gently closed lips
 Cheilion (Ch) The point located at each labial commissure
 Soft tissue B point (B') The deepest point on the facial midline, between the lower lip and chin
 Lower incisor tip (L1) The midpoint of the incisal edge of the right mandibular central incisor.
 Upper lip prominent (UP) A line parallel to the passing Ls to Stm touched the outer most point on upper lip from lateral view
 Lower lip prominent (LP) A line parallel to the passing Li to Stm touched the outer most point on upper lip from lateral view
Reference planes
 Horizontal plane A plane constructed with the right orbitale, the right porion, and the left porion (Frankfort horizontal (FH) plane)
 Coronal plane A plane constructed with the right frontozygomatic suture (FSZ) and left FZS, perpendicular to the FH plane
 Sagittal plane A plane constructed with nasion, perpendicular to the FH and coronal planes