中国人颏孔及下颌孔的观察

A STUDY OF THE MENTAL AND MANDIBULAR FORAMEN IN THE CHINESE

观察250个中国人颏孔及下颌孔的位置所得到的结果如下:1.78.4%的颏孔是在第2前臼齿的下方。2.多颏孔以下颌骨数计算有5.2%,以侧计算有2.8%。3.颏孔大致是在下颌体长的前1/4的地点,下颌体高的中间。4.下颌孔大致是在下颌支高的中央,稍靠後缘。

Mental and mandibular foramen of 250 Chinese mandibles were studied.It wasfound that the mental foramina wer located as follows:below apex of the lst premolar--1.2%on the right,0.4%on the left;between the lst and 2nd premolar--18.8%on theright,7.6%on the left;below apex of the 2nd premolar--74.4%on the right,82.4%on the left;between the 2nd premolar and lst molar--5.6%on the right,8.8%on the left;below apex of the lst molar--none on the right,0.8%on the left.Theaverage distance of the anterior margin of the foramen to the mental symphysis was26.5 mm.on the right,26.8 mm.on the left;to the posterior border of the ramus,70.0 mm.on the right,69.0 mm.on the left;to the alveolar border,15.5 mm.on the right,15.2 mm.on the left;to the basal margin,15.6 mm.on the right,15.5 mm.on the left.With regard to the occurrence of the multiple mental foramina,it was found tobe 1.2%on the left 1.8%on the right,and 0.4%on both sides simultaneously.Theapproximate position of the mandibular foramen was slightly higher than the midpointof the ramus and is a little to the posterior border of the ramus.The average distanceof the lowest margin of the foramen to the mandibular notch was 22.5 mm.on the right,25.1 mm.on the left;to the basal margin,25.5 mm.on the right,27.6 mm.on the left;to the posterior border,15.8 mm.on both sides;to the anterior border,20.0 mm.on theright,20.6 mm.on the left.Various observations on this subject by other authors wereintroduced and discussed.