All soft tissue measurements were greater except for gnathion
in low angle group in men than in women.
* Mandibular angle left/right (MAL/MAR) (angle between gnathion
, gonion, lateral condyle).
For example, computed total face height (trichion to gnathion
distance) by the novel image-processing algorithm was converted to actual life size or distance as follows:
Using the sliding caliper, the following parameters were recorded : (1) the upper naso-aural distance (n-obs)--between nasion and otobasion superius; (2) the lower naso-aural distance (n-obi)--between nasion and otobasion inferius; (3) the upper subnasale-aural (sn-obs)--between the subnasale and otobasion superius; (4) the lower subnasale-aural (sn-obi)--between the subnasale and otobasion inferius; (5) the upper gnathion-aural (gn-obs)--between the gnathion
and otobasion superius; and (6) the lower gnathion-aural (gn-obi)--between the gnathion
and otobasion inferius.
Aging causes progressive loosening of the tissues of the lower face and neck, which manifests as narrowing of the cervicomental angle (between the neck and the lowest point under the chin) and the gnathion
angle (between the lowest point trader the chin and the most anterior or prominent point on the front of the chin).
No significant differences in mandibular growth as measured from articulare to gnathion
were found between the groups during the first year of treatment.
Goodfriend (18) suggested that the distance from the pupil of the eye to the junction of the lips equaled that from the sub-nasion to the gnathion
. Harvey (19) conducted a survey of the Willis measurement on 100 young men with natural teeth.
George (1987, 1993) defined two points under the chin, the gnathion
and the menton.
The higher value of the subnasale to gnathion
distance recorded in control groups shows that prognathic maxillary profile is more prevalent in control subjects than OSAS.
One way is that a tangent is drawn to the posterior border of mandibular ramus and it is intersected with another line which passess through the goinion and gnathion
of the mandible.11
Caption: FIGURE 1: Points and plains used in cephalometric analysis: Gl; (soft-tissue glabella), Prn (pronasale), Cm (columella), Sn (subnasale), Ls (labrale superius), Li (labrale inferius), Pg; (soft-tissue pogonion), Pg (osseous pogonion), Gn (gnathion
), Me (menton), Go (gonion), Ba (basion), Co (condylion), Po (porion), Pt (pterygoid point), S (sella), PNS (posterior nasal spine), ANS (anterior nasal spine), N (nasion), Or (orbitale), Ap + 1 (apicale superius), Ap - 1 (apicale inferius), In + 1 (incisale superius), In - 1 (incisale inferius), NSL (nasion-sella line), FA (facial axis), NL (nasal line), MP (mandibular plane), FH (Frankfort horizontal), E (Ricketts' Esthetic line), and S (Steiner's line).
(d) Subnasale to gnathion
= lower facial height measured when mandible is at rest position.
The morphological facial height was measured with digital slide caliper with scale from nasion (n) to gnathion
The mandibular plane (registered on gonion and gnathion
) moves towards the horizontal such that the mandibular plane angle (mandibular plane to the Frankfort horizontal) decreases.
(b) Lateral cephalometric radiographs skeletal reference points: Nasion (N), sella (S), orbitale (Or), porion (Po), condylon(Co), anterior nasal spine (ANS), posterior nasal spine (PNS), point (A), point (B), gnathion
(Gn), menton (Me), and gonion (Go).