Uchida Y, Akiyoshi T, Goto M, Katsuki T
Department of Anatomy, Saga Medical School.
Okajimas Folia Anat Jpn. 1994 Oct;71(4):227-47. doi: 10.2535/ofaj1936.71.4_227.
Standardized photographs (lateral and basal view) of fetal mandibles (n = 80) were taken. Outline segments (from gnathion to condylion, on the coronoid process and from infradentale to gnathion in lateral view; and on the inferior margin in basal view) were analyzed into sine curves, according to Fourier series. Using the calculated Fourier coefficients, we statistically examined how mandibular shape changed with fetal growth. Materials were classified into four groups on the basis of the body length (BL): 100 < or = BL < 200 mm (BL1, n = 20); 200 < or = BL < 300 mm (BL2, n = 20); 300 < or = BL < 400 mm (BL3, n = 20); and 400 < or = BL < or = 500 mm (BL, 4 = 20). Statistical analyses were all done on these stature groups. On the outline from gnathion to condylion, the constant and the first term phase showed statistically greater values in BL4 than in the other groups, as assessed by t-test. The first term phase for the coronoid process significantly decreased with increments in stature in the canonical disciminant analysis. On the outline from infradentale to gnathion, although the cumulative contributions of the first two terms were constant (about 85%) in all four groups, the relative contributions with growing stature decreased in the first term and increased in the second term. The mean of the phase in the first term indicated slightly more than -90 degrees in BL1, and was less than -90 degrees in BL2 to BL4. The averages of the second term phases presented little change from BL1 to BL3, and were close to -100 degrees. From the canonical discriminant analysis, the constant was great and the first term amplitude was small in BL1 and BL4, and the constant was small and the first term amplitude was great in BL2 and BL3. Also, the second term amplitude in BL4 indicated a significantly bigger volume than in BL3. The constant for the inferior margin manifested statistically significant increments in BL2 to BL4, as assessed by t-test. We interpret the results as follows: 1. On the outline from gnathion to condylion, anteroinferior shift occurs in BL4, resulting in an acute gonial angle. The change of angle during the prenatal period precedes the postnatal findings that bring about a progressive decrease in the gonial angle. 2. The tip of the coronoid process indicates a forward shift with increasing fetal body stature.(ABSTRACT TRUNCATED AT 400 WORDS)
拍摄了80例胎儿下颌骨的标准化照片（侧位和基底位）。根据傅里叶级数，将轮廓线段（侧位观从颌下点到髁突、喙突，以及从下齿槽点到颌下点；基底位观为下颌下缘）分析为正弦曲线。利用计算出的傅里叶系数，我们从统计学角度研究了下颌骨形状随胎儿生长的变化情况。根据体长（BL）将材料分为四组：100≤BL＜200mm（BL1组，n = 20）；200≤BL＜300mm（BL2组，n = 20）；300≤BL＜400mm（BL3组，n = 20）；400≤BL≤500mm（BL4组，n = 20）。所有统计分析均在这些身高组上进行。通过t检验评估，在从颌下点到髁突的轮廓上，BL4组的常数和第一项相位在统计学上比其他组的值更大。在典型判别分析中，喙突的第一项相位随身高增加而显著降低。在从下齿槽点到颌下点的轮廓上，虽然所有四组中前两项的累积贡献率是恒定的（约85%），但随着身高增长，第一项的相对贡献率降低，第二项的相对贡献率增加。第一项相位的平均值在BL1组略大于-90度，在BL2组至BL4组小于-90度。第二项相位的平均值从BL1组到BL3组变化不大，接近-100度。从典型判别分析来看，BL1组和BL4组的常数大，第一项振幅小，而BL2组和BL3组的常数小，第一项振幅大。此外，BL4组的第二项振幅在统计学上比BL3组大得多。通过t检验评估，下颌下缘的常数在BL2组至BL4组有统计学意义的增加。我们对结果的解释如下：1. 在从颌下点到髁突的轮廓上，BL4组出现前下移位，导致下颌角变锐。产前时期角度的变化先于出生后下颌角逐渐减小的表现。2. 随着胎儿身体身高的增加，喙突尖端向前移位。
