This study was undertaken to investigate the midline having the least difference between the right and left structure among the lines thawt had been used in the study of the craniomaxillofacial asymmetry. The sample of this study consisted of
twenty six
Korean girls(average 18.9 years old) having normal faclal appearance and occlusion. On the frontal cephalometric films of the sample. We divided the whole cranionmaxil-lifacial area into four portions, i.e., cranial, upper facial, lower facial,
and
dental prtion.
So. We have found the midlines having the least difference in the whole craniomaxillofacial area itself, and in the each divided four portions. Furtherly in the other portions from aimed portion.
@ES The findings were as follow:
@EN 1. In the whole craniomaxillofacial area, the connecting line between crista galli and anterior nasal spine and the perpendiculiar bisecting line between right and left foramen rotundums were suitable for the midline.
2. In the cranial portion. Established all six lines were suitable for midlines. In the other portions, the perpendicular bisection line between both condylion. The line passing the contact point between right and left mandibular central
insisiors
among the perpendicular lines between right and left mandibular central incisial tips were suitable midlines for evaluating the asymmetry of cranial portion.
3. In the upper facial portion, the perpendicular bisecting line between right and left zygions was the most suitable midline. In the other portions, the line between the crista galli and the most superior point of the odontoid process. The
perpendicular bisecting line between right and left gonions, the perpendicular bisecting line between right and left condylions, and perpendicular bisecting line between right and left foramens rotundum were suitable midlines for evaluating the
asymmetry of the upper facial portion
4. In the dental portion, the perpendicular bisecting lines between right and left buccal cusps of both maxillary first molars and between right and left mandibular first molars were suitable midlines. In the other portions, the perpendicular
bisecting
line between right and left landmarks crossing the lesser wing of the sphenoid bone and orbit, the perpendicular bisecting line between right and left mental formens. And the connecting line between crista galli and prosthion were suitable
midlines
for
evaluating the asymmetry of dental portion.
5. In the lower facial protion, the perpendicular bisecting lines between right and left condylions and between right and left gonions were suitable midlines. In the other portions, the line between the crista galli and anterior nasal spine, the
perpendicular bisecting line between right and left foramen rotundums. And the perpendicular bisecting lines between right and left buccal cusps of both mandibular first molars and between right and left maxillary first molars were suitable
midlines for
evaluating the asymmetry of the lower facial portion.
KOREA J ORTHOD 1993 ; 23(1) : 1-15.
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