The Study Of Sex Determination Of Sacral Basis In CT 3D Reconstruction

Pelvis is the most distinguishable part in sex determination of skeleton anatomy and is also of significance in forensic identification in special condition. Since pelvis might not be preserved completely in many severe disasters and in archeology, discrimination of sacrum will be still needed. Because of the complexity of sacrum anatomical structure and unique function to bearing weight, the study of sex determination of sacrum did not reach an satisfying conclusion over the whole world.There were studies on sex differences of sacrum in our country since 1980s last century, for lack of suitable samples, the level of statistics and also the complexity of sacrum itself, almost all the studies concentrated merely on the difference of sacrum instead of sex determination, which was of primary level. Apart from this, the disparity in accesses of samples and methods of statistics also caused obvious differences between internal and international studies. On the basis of studies for sacrum difference and discrimination and application of statistic methods widely used abroad, we made an analysis of sex determination of sacrum and new evidence were hoped to be brought in the analysis of Chinese sacrum samples through the analysis of discrimination, which may be of use in archaeology.99 CT images of Chinese sacrum samples were taken randomly, among which 50 were male and 49 were female. The average age of volunteers were 40,which ranged from 18 to 56. CT 3D reconstruction were applied to each sample and tools of CT workstation were used to erase the soft tissues and extra skeleton structure, S1 maximum transverse diameter (S1 m.t.d), S1 maximum longitudinal diameter (S1 m.1.d), S1 area (S1area), Maximum superior breadth of sacrum (S m.s.b) were measured and analyzed with spss17.0 to work out whether they were of difference between male and female. These primary results were put in contrast with internal articles and single variate,2 variance and 4 variance were in sequence used to construct discrimination function analysis and coefficients and correct rate figured out were taken down for comparison with results served by international articles on sacrum reconstruction and sex determination in skeleton 3D reconstruction, finally primary conclusion can be made on feasibility of sex determination of sacral basis in CT 3D reconstruction.There were obvious difference between average data of male and female, which were consistent with results accessed by direct measurements from cadaver skeleton samples. And the primary analysis can also provide evidence to demonstrate that the difference were not merely caused by height. In the discrimination function analysis, single variate reached a correct rate of 76% and doule variance 79%. While at four variance analysis,the rate merely reached 76% after elimination one of the variance in stepping process of the analysis, which is unsatisfying considering other results. During the contrast with associated articles abroad, the correct rate cannot provide an sufficient evidence to set up equations to make primary sex determination of sacrum(which needs at least an 80% rate of correction), but for the discrimination rate, our study were in accordance with other countries and regions(at the rate of 66%-72%),so we can deduce that the sacrum difference between male and female varies from nations and countries and discrimination function analysis may be unsuitable for Chinese sacrum...