Fig 1.
Reference points and planes, and measurement lines on the CT images.
A. Measurement lines on the median sagittal plane of the cranium. The volume of interest (VOI) was limited to the maxillofacial area and the anatomical landmarks are identified. The sum of the distance from ‘n’ to the ‘alv plane’ (“n-alv distance”) and from the ‘alv plane’ to ‘ba’ (“alv-ba distance”) was defined as a reference of the cranial anterior-posterior length, termed “CA-P”. The distance from ‘pr’ to the ‘alv plane’ was defined as the anterior-posterior length of the maxilla, termed “MA-P”. ‘alv’: the point where the midline of the palate is intersected by a straight tangent connecting the posterior borders of the alveolar crests. ‘n’: the point of intersection of the nasofrontal suture and the mid-sagittal plane. ‘pr’: the most anterior point on the alveolar border of the maxilla. ‘ba’: the point where the anterior margin of the foramen magnum is intersected by the mid-sagittal plane. B. Definition of ‘alv’ plane. The coronal plane which is orthogonal to the FH (Frankfurt horizontal plane) and parallel to the line connecting the left and right ‘po’, and passes through ‘alv’, was defined as the ‘alv plane’.
Table 1.
Evaluation of maxillary deformities from 3D-CT images.
Fig 2.
Reconstructed stereoscopic CT images of the maxilla.
Two severely deformed cases, A (ID 9) and B (ID12), and two control cases, C (ID C1) and D (ID C3), are shown. The front, left side, and bottom view of the cranium are shown from top to bottom. The deformities of the anterior nasal spine and the alveolar process are easily observed in A and B. The result is that the retracted surface of the central maxilla and the regression of the alveolar process look nearly symmetric and crescentic. Arrows indicate the anterior nasal spine (ANS) or the corresponding point.