Table 1.

Landmark Definition^a

Landmark	Variable Name	Skeletal Landmark Definition
Sella	Sella	The midpoint of the pituitary fossa as determined by inspection
Nasion	Nasion	The most antero-inferior point on the frontal bone at the middle of fronto-nasal suture
Basion	Basion	The inferior-most point on the anterior margin of the foramen magnum in the middle
Porion	Porion_R; Porion_L	The most superior and lateral point at the external enterance to the auditory meatus
Orbitale	Orbitale_R; Orbitale_L	The most inferior point of the lower border of the bony orbit
Crista galli	CristaG	The most superior and anterior point on the median ridge of bone that projects upward from the cribriform plate of the ethmoid bone
Nasal bone	NasBone	The middle of the nasal bone tip at its most inferior end
Fronto-zygomatic suture	FroZyg_R; FroZyg_L	The most anterior point at the intersection of the frontozygomatic suture on the inner rim of orbit
Foramen spinosum	ForSpin_R; ForSpin_L	The center of the opening of foramen spinosum in the greater wing of the sphenoid bone, situated lateral to the foramen ovale
Temporal fossa	TempFos_R; TempFos_L	The most superior and lateral point of inferior zygomatic arch border, above condylar head as seen from the sagittal perspective
ANS	ANS	The anterior-most point of the anatomic anterior nasal spine
PNS	PNS	The posterior-most point of the anatomic posterior nasal spine
Point A	Point A	The deepest point on the curvature of the surface of the maxillary bone between ANS and the alveolar crest in the middle of maxilla
Key ridge	KeyRig_R; KeyRig_L	The most inferior point of the zygomaticomaxillary ridge along the suture between the zygomatic bone and the maxillary bone
Jugale	Jug_R; Jug_L	The intersection of the outline of the maxillary tuberosity and the zygomatic buttress
Pogonion	Pogonion	The anterior-most point on the chin in the midline of the mandibular symphysis
Menton	Menton	The inferior-most point on the chin at the midline of the mandibular symphysis
Point B	Point B	The deepest point on the curvature of the anterior border of the mandible between pogonion and the alveolar crest of the lower incisors at the middle of mandible
Condyle	Condyle_R; Condyle_L	The most superior (sagittal perspective) and the middle (frontal perspective) point on the contour of the condyle head
Gonion	Gonion_R; Gonion_L	The most inferior point on the curvature of the angle of the jaw where the body of the mandible meets the ramus
Mental foramen	MentFor_R; MentFor_L	The center of mental foramen located on the external surface of the mandible
Central incisor	UR1_MInc; UL1_Minc;	The most inferior and mesial point along the incisal edge of central incisor
Mesio-incisal edge	LR1_MInc; LL1_Minc
Central incisor	UR1_DInc; UL1_Dinc;	The most inferior and distal point along the incisal edge of central incisor
Disto-incisal edge	LR1_DInc; LL1_DInc
Central incisor	UR1_Apex; UL1_Apex;	The most apical point on the root of central incisor
Root apex	LR1_Apex; LL1_Apex
Canine	UR3_MCon; UL3_Mcon;	The most lateral point on the mesial contact point of canine
Mesial contact point	LR3_MCon; LL3_MCon
Canine	UR3_DCon; UL3_Dcon;	The most lateral point on the distal contact point of canine
Distal contact ooint	LR3_DCon; LL3_DCon
Canine cusp	UR3_Cusp; UL3_Cusp;	The most occlusal point on the cusp of canine
	LR3_Cusp; LL3_Cusp
Canine root apex	UR3_Apex; UL3_Apex;	The most apical point on the root of canine
	LR3_Apex; LL3_Apex
First premolar	UR4_BCusp; UL4_Bcusp;	The most occlusal point on the buccal cusp of first premolar
Buccal cusp	LR4_BCusp; LL4_BCusp
First molar	UR6_MBCusp; UL6_MBCusp;	The most occlusal point on the mesiobuccal cusp of first molar
Mesiobuccal cusp	LR6_MBCusp; LL6_MBCusp
First molar	UR6_DBCusp; UL6_DBCusp;	The most occlusal point on the distobuccal cusp of first molar
Distobuccal cusp	LR6_DBCusp; LL6_DBCusp
First molar	UR6_MLCusp; UL6_MLCusp;	The most occlusal point on the mesiolingual cusp of first molar
Mesiolingual cusp	LR6_MLCusp; LL6_MLCusp
First molar	UR6_DLCusp; UL6_DLCusp;	The most occlusal point on the distolingual cusp of first molar
Distolingual cusp	LR6_DLCusp; LL6_DLCusp
Upper first molar	UR6_MBApex; UL6_MBApex	The most apical point on the mesiobuccal root of upper first molar
Mesiobuccal root apex
Upper first molar	UR6_DBApex; UL6_DBApex	The most apical point on the distobuccal root of upper first molar
Distobuccal root apex
Upper first molar	UR6_PApex; UL6_PApex	The most apical point on the palatal root of upper first molar
Palatal root apex
Lower first molar	LR6_MApex; LL6_MApex	The most apical point on the mesial root of lower first molar (if there is bifurcation, then mesiobuccal root)
Mesial root apex
Lower first molar	LR6_DApex; LL6_DApex	The most apical point on the distal root of lower first molar
Distal root apex
Lower first molar	LR6_MBGroove;	The point at the height of counter of the buccal groove of lower first molar
Buccal groove	LL6_MBGroove

^aL indicates left; LL, lower left; LR, lower right; R, right; UL, upper left; UR, upper right.