Childhood change in depth and height of the upper face, with special reference to Downs' A point

Abstract This study contributes to the present knowledge on growth in size of the human face during the decade of ontogeny between the ages of 5 and 15 years. Longitudinal data are analyzed for two anteroposterior dimensions in the region of the osseous midface and for three vertical dimensions in the region of the anterior profile of the osseous midface and upper face. These data are derived from norma lateralis roentgenograms taken at biennially spaced ages in twenty orthodontically normal white girls. Results are presented for facial size at selected ages, facial change during selected periods, associations among measures of facial size and change, and variations among the growth patterns of individuals for the different dimensions studied. In this connection, our findings are as follows: 1. 1. With reference to nasion, the location of point A lies more inferiorly with age. At age 5, the obtained mean for distance from nasion to point A is 43.4 mm. The obtained mean for this distance at age 15 is greater by 11.6 mm., or 27 per cent. 2. 2. Expressed in terms of vertical distance from the nasal floor to the level of the most anterior point in the maxillary alveolar region, point A has a higher location at age 5 than at age 15. On the average, the relative position of point A is 37 per cent below the nasal floor at age 5 and 47 per cent below the nasal floor at age 15. 3. 3. Typically, the maxillary profile below the level of the anterior nasal spine has a less concave contour at age 5 than at age 15. Increment data are analyzed for facial depths from a postfacial line to point A and to the most anterior point in the maxillary alveolar region. Over the decade of ontogeny investigated, the average increase for the depth to point A is 9.8 mm. and average increase for the more inferior depth is greater by 1.8 mm., or 18 per cent. 4. 4. There is a tentative indication that the facial height from nasion to point A and the midface depth from point A to a postfacial line are not highly correlated variables. Further, it appears that there is almost no relationship between childhood gain in distance from nasion to point A and gain during childhood in distance from point A to a point at the rear of the face. 5. 5. With respect to face height from nasion to point A, moderate inverse associations are obtained for size at age 5 with increase in the ensuing decade and for gain during the quadrennium following age 5 with gain in an equal period following age 11. With respect to midface depth from point A to a postfacial line, correlations near zero are found for size at age 5 with increment in the subsequent decade and for increments in the quadrennia from ages 5 to 9 and 11 to 15. 6. 6. Growth trends in individuals during the period between ages 5 and 15 are more varied for some facial dimensions than for others. For height from nasion to point A, and also for two measures of midface depth, the predominating characteristic of curves representing individual girls is ascent with age. Characterized further, individual trends for each of these dimensions are largely classifiable into two varieties. Curves for vertical distances from the nasal floor to point A and from point A to the level of the anteriormost point in the maxillary alveolar region exhibit more variation in direction during segments of the decade and greater diversity in over-all pattern.