重新审视A点。

Point A revisited.

作者信息

Jacobson R L, Jacobson A

出版信息

Am J Orthod. 1980 Jan;77(1):92-6. doi: 10.1016/0002-9416(80)90227-4.

Abstract

Point A cannot be accurately identified in all cephalometric radiographs. In instances where this landmark is not clearly discernible, an alternative means of estimating the anterior extremity of the maxillary base is shown. A point plotted 3.0 mm. labial to a point between the upper third and lower two thirds of the long axis of the root of the maxillary central incisor was found to be a suitable point (estimated point A) through which to draw the NAE line and one which most closely approximates the true NA plane.

摘要

在所有头颅侧位片中，A点并非都能被准确识别。在该标志点不清晰可见的情况下，展示了一种估计上颌骨基部前端的替代方法。通过在上颌中切牙根长轴上三分之一与下三分之二交界处的点唇侧3.0毫米处标记一个点（估计A点），发现该点是绘制鼻根点 - A点（NAE）线的合适点，并且最接近真实的鼻根点 - 上齿槽座点（NA）平面。