Sex determination by discriminant function analysis of lateral cranial form.

To sex the cranium, morphological features of cranial specimens were quantified with a personal computer that automatically measures distance and gradient for 39 craniometric points in the lateral contour line of the skull, which were digitized by a tablet digitizer connected to the computer. Specimens used for discriminant analysis were 50 male and 50 female adult Japanese skulls. The lateral contour showed sex differences in the nasal bone, supraorbital ridge, forehead and vertex. The nasal bone and supraorbital ridge were more developed in male contour line, and the forehead was more rounded in female contour line. But compared with the supraorbital ridge and forehead, the vertex had a wide variety of contour lines in both sexes. The vertex seemed to be less reliable as the indicator of sex. The sex differences were better reflected by gradient than distance. From variables of the gradient and distance showing significant sex differences, the discriminant function was derived and tested in 21 other specimens (13 male and 8 female skulls). The mean ratio of correct sexing of the human skull by the discriminant function was 86%.     

Independent instances of "souvenir" Asian skulls from the Tampa Bay area

In the summer of 1984, police in Pinellas County, Florida, confiscated six identically colored imported Asian skulls (in a shipping case) from a private citizen. In May 1988, in nearby Hillsborough County, police confiscated a very similar skull from another private citizen, who allegedly had found it in an abandoned house. Aside from slight color differences between the six found in Pinellas County and the one found in Hillsborough County, the skulls are virtually identical in their osteological characteristics and condition and in the vital statistics derived from each. Each skull is as clean and dry as those typically sold by commercial scientific supply outlets in the United States. Each is edentulous (primarily premortem), between approximately 20 and 60 years of age at death, and morphologically Asian. Five of the seven are morphologically male, one is morphologically female, and one is a mosaic with respect to gender-related features. Police, medical examiners, coroners, and forensic anthropologists should be aware of such "souvenir" specimens, in the event that they encounter similar skulls. Discriminant function analyses for race and sex yield considerably conflicting results, which underscores the need for using extreme caution when interpreting forensic science estimates based on such techniques.     

西南地区成人面颅骨的性别判定

目的建立适合西南地区成人的颅骨性别判定函数。方法性别明确的颅骨67个,测量颅骨最大长、颅骨最大宽、颅高等16项指标,所得数据进行统计学分析,建立单一变量及多变量性别判定方程,并对5个无名颅骨进行回带检验。结果 16项指标中有13项存在显著的性别差异,男性大于女性,单变量函数推断性别以鼻高(男78.4%,女83.3%)、颅骨最大长(男83.8%,女73.3%)准确率较高。多变量性别判定函数以颅周长、鼻高贡献最大,判定准确率男89.2%,女90.0%。结论单变量推断颅骨性别以鼻高或颅骨最大长较为理想,但以颅周长、鼻高联合推断性别准确率更高。     

Determination of sex and race from the subpubic angle in Ugandan subjects

The accurate determination of sex and race are important tools to forensic and physical anthropologists. In this study, the sex and race of 205 adult Ugandans were determined from the antero-posterior radiographs of the pelvis by measuring their subpubic angles. The angle ranged from 50 to 140 degrees with a mean of 93.86 degrees and standard deviation (SD) of 21.12 degrees for males and 75 to 155 degrees with a mean of 116.11 degrees (SD, 17.79 degrees) for females. The angle was significantly wider in women than men (P < 0.05), as indeed has previously been shown in other population groups studied. Using the demarking point method, 31.82% of Ugandan men and 10.53% of Ugandan women could be accurately sexed. However, more Malawians of both sexes previously studied had lower values for the angle and could be more accurately sexed. This study has also documented regional and racial variability of this angle among different population groups previously documented. Using the watershed subpubic angle derived from the means of this study and those of previously documented studies, 63% of Ugandans and 71% of Malawians could be accurately assigned to the black race. This method is recommended to physical and forensic anthropologists in the developing world.     

Fourier analysis of the forehead shape of skull and sex determination by use of computer

The forehead shape of the skull was quantified with the Fourier analysis method by using 100 male and 100 female radiographic lateral views of the skull, and sex difference in the forehead shape was studied. Furthermore to predict the sex of cranial specimens, an automated sexing computer system based on the quantification was created. The effectiveness of the system was evaluated by checking 56 male and 56 female specimens of skulls. This system was proved to discriminate male and female skulls from forehead shapes with 85% accuracy.     

现代人面颅角度测量的种族差异性

目的探索面颅角度指标在种族鉴定方面的差异性。方法选取现代人头骨57例,其中中国黄种人头骨30例（女性9例,男性21例）,包括吉林1例,河北5例,山东4例,青海4例,安徽4例,江西3例,云南3例,贵州3例,广西3例。欧洲自种人头骨27例,性别不详,取自欧洲Zellemdorf、Vresovice、Kysperka3地。按体质人类学测量方法,通过参考相关文献和对颅骨形态特点的观察,设计面颅左侧眶角、右侧眶角、鼻颌角3个角度指标进行测量。对测量数据进行描述性统计分析和两独立样本之间的t检验。结果3个角度指标在种族差异性方面,眶角的种族差异性具有显著统计学意义（P〈0．01）,而鼻颌角之间的种族差异性无统计学意义（P〉0．05）。结论有些角度指标显示出明显的种族差异性,今后需要加强此方面的研究。     

Metric assessment of the "mastoid triangle" for sex determination: a validation study

Recently, a metric approach to skeletal sex determination was published by Paiva and Segre which is based on the summation of two triangular areas defined by three distinct craniometric landmarks: Porion, Mastoidale, and Asterion. According to the authors, values for the total triangle > or =1447.40 mm(2) are characteristic for male crania, while values < or =1260.36 mm(2) are indicative of female skulls (95% confidence). In order to evaluate the method's validity, two sex- and age-documented samples of different provenience were analyzed (N=197). The results show that while the indicated measurements display significant sex differences, the technique is of little practical meaning where a single individual must be independently classified. It is hypothesized that differences in the expression of sexual dimorphism as well as a population-specific variability of the asterion location undermine the value of the mastoid triangle as a sex determinant.     

The reliability of sex determination of skeletons from forensic context in the Balkans

In this study we have tested the applicability of morphological methods for sex assessment, based on seven pelvic and nine cranial traits, using contemporary Balkans population. The material involved in the study comprises 262 pelvic bones and 180 skulls of male individuals from two mass graves in Serbia. The material was examined separately by an experienced and an inexperienced physical anthropologists. Sex was correctly estimated by the experienced anthropologist in 100% of individuals using all of the 16 pelvic and cranial criteria. In fact, sex differences in pelvic morphology were large enough to allow sexing the individuals with 100% accuracy. Among seven features observed on the pelvic bones, the least reliable single sex indicator was the width of the great sciatic notch (with accuracy of 79.15%). Looking at the skull alone, sex was correctly determined in 70.56% cases. It was shown that the most accurate single indicators among cranial methods was the robustness of the mandible (with accuracy of 70.93%), while the sharpness of the supraorbital margins was the least reliable indicator demonstrating accuracy in only 28.75% of crania. Examination of the sample by an individual with training in physical anthropology, but no case experience, suggests that experience is likely to contribute moderately to the accuracy of the sex determination. Namely, the inexperienced anthropologist accurately assessed the sex of the sample 95.04% of the time; 4.06% less accurate than the experienced anthropologist. The two anthropologists showed the least agreement in scoring the ventral arc and composite arc on the pelvic bones.     

An Examination of Defendant Sex Disparity in Capital Sentencing: A Propensity Score Matching Approach

Although much prior work has examined the influence of extralegal factors on jury capital sentencing decision-making, the influence of defendant sex has been largely omitted from previous investigations. Using propensity score matching methods, the current study analyzes data from the North Carolina Capital Sentencing Project to examine whether “sex matters” in capital sentencing. Findings demonstrated that prior to matching there was a significant difference in the likelihood of receiving the death penalty for female and male defendant cases; however, after matching cases on an array of legal and extralegal case characteristics, these differences were no longer significant. Further results revealed that male defendants’ cases included different aggravating and mitigating factors than female defendants’ cases and that female defendants had limited “paths” to capital trials. Findings suggest that any apparent sex effects that are observed in capital sentencing stem from real differences in the case characteristics found in female and male defendants’ cases rather than any direct effects of defendant sex on jury decision-making. Study limitations and implications for death penalty research are also discussed.     

The roughness of the supranasal region--a morphological sex trait

The supranasal region often attracts attention by a remarkable rough and jagged quality of the bony surface caused by an irregular supranasal suture and additional holes and pores. Some authors point out that there is a positive relation between the supranasal suture, the superciliar arches, and the forehead contour. For this a relation to sex is conceivable. This present study was done to prove the value of this morphological trait for sexing skulls.A total of 80 human skulls of known sex (40 females, 40 males) were collected from autopsy material used in anatomy teaching classes and from forensic cases. The mean age of the female sample was 70.98 years (minimum 38, maximum 93), that of the male sample was 74.10 years (minimum 57, maximum 99). To quantify the roughness of the supranasal region the calculation of the box-counting dimension was used. The results were normally distributed in both, the male and female group. The male dimension values were well grouped (maximum 1.51111, minimum 0.98765, mean 1.26159, S.D. 0.12268, 95% CI 1.22236-1.26604) whereas the female showed a wide range (maximum 1.46744, minimum 0.44755, mean 1.15052, S.D. 0.21388, 95% CI 1.08212-1.21892), widely overlapping the male range. Statistical analysis showed that there was a less than 1% probability that the female box-counting dimension was lower than the male by chance (P-value 0.00593). For this results the admission of the trait 'quality of the supranasal region' into a catalogue of features regarding morphognostic sex determination following the scheme: hyperfemininity: very smooth and regular--femininity: more smooth and regular--indifferent--masculinity: more rough and irregular--hypermasculinity: very rough and irregular, seems to be justified.     

Determination of race and sex of the human skull by discriminant function analysis of linear and angular dimensions

The race and sex of the human skull can be determined by craniometry. In this paper we suggest that a large number of craniometric measurements does not necessarily give the best possible discrimination for race and test the performance of subsets of variables drawn from various skull regions, or extracted mathematically on the basis of their discriminatory power. We also suggest that the best discriminators for race are not necessarily the best for sex, and that skulls of unknown provenance are best tested first for race and then for sex, using different variables for each purpose.     

Plastic face reconstruction as a possibility for identifying unknown skulls (II). An evaluation of the reliability of the reconstruction technic by a double-blind trial

In a double blind-trial two examiners reconstructed the soft tissue on lifelike casts of 12 skulls. They worked independently after having been given information about age, sex and constitution of the person in question and following a reconstruction plan based on the morphology of the skull. The comparison of the completed reconstruction with each other chiefly showed approximate to far-reaching degrees of resemblance and conformity. The comparison of reconstructions and photographs of the individuals also showed predominantly approximate to far-reaching likeness of the general impression, and, with one exception, at least little likeness was achieved. The reconstruction of soft tissue on the skull proved to be a relatively useful method of identifying unknown skulls, provided information on the colour and length of the hair, and possibly on the hairstyle as well, is at the examiner's disposal.     

Sex and Experience: Modeling the Public’s Perceptions of Justice, Satisfaction, and Attitude Toward the Courts

The purpose of the present study is to examine the influence that sex has on the interconnection between justice, satisfaction with the courts, and attitudes toward the courts. Using national level polling data, the results show that different forms of justice coalesce into a latent measure of justice. Further, the results show that sex differences in our latent measure of justice do exist. In addition, those with experience with the course have a negative attitude toward the court system. Finally, the results show that the impact of justice on attitude toward the court system is partially mediated by satisfaction with the court. Policy implications are discussed.     

Recent human sexual dimorphism study using cephalometric plots on lateral teleradiography and discriminant function analysis

Abstract:  The examination of skull sexual dimorphism has been the subject of numerous morphologic and craniometric studies, but the disadvantage of these studies is that they are dependent on the experience of the operator and involve subjectivity. In 1996, a team from Taiwan refined the methods enabling the sex of an individual to be determined using cephalometric plots made from lateral teleradiography. To validate their work using a European population, 114 dry skulls (59 men and 55 women) were examined. Cephalometric plots were made on lateral teleradiography with an orthodontic software and 18 cephalometric variables were analyzed. Sex was determined with 95.6% accuracy using the 18 variables discriminant function. A subset of eight variables was selected and could predict sex with the same accuracy. In conclusion, it can be said that skull-sexing methods using lateral teleradiography seem always suitable but the most indicative variables could differ relative to the ethnic population concerned.     

西南地区成人男性颅骨的相关回归分析

目的研究颅骨部分测量指标间的相关性,以期建立在对破损颅骨进行颅骨面貌复原时,利用尚存指标推断缺失指标的方法。方法用人体骨骼测量仪对41个男性颅骨的颅长、颅宽、颅高等14个指标进行测量,将测量值输入SPSS统计软件,找出相关性好的指标,建立各指标间相互推断的回归方程。结果部分测量指标间呈中度以上相关,应用逐步回归的方法得出回归方程24个,方差检验均具统计学意义(P<0.01)。结论本研究所建立的回归方程可为法医人类学和考古人类学的颅骨修复提供备选方法。     

Methodology for estimating endocranial capacity in a modern European population

Various methods have been published in the literature to estimate endocranial capacity. These are based on mathematical equations using measurements made directly on the skull or indirectly from X-rays, by filling the skull with various materials, by endocasts both physical and virtual (using 3D CT-scan reconstructions). Each method has its advantages, limits and drawbacks. A useful method is one that is simple, time-efficient, cheap, and reproducible. For this study we estimated endocranial capacity by filling the skull with calibrated glass beads. We used a thorough protocol of tamping to ensure results reproducibility. Intra- and inter-observer trials showed no significant differences. The method was applied to 130 recent French (West European) skulls (65 males and 65 females). Sexual dimorphism was studied using logistic regression functions, discriminant analysis, and neural network. The best results were obtained using the neural network, built with two hidden nodes in the hidden layer and one output node, and trained with a steepest descent algorithm. Our tests show that there is obvious sexual dimorphism (p < 10(-5)) of the weight of the skulls (623.44 ± 106.83 g in males; 548.07 ± 94.57 in females), the weight of the glass beads used to fill the skulls (2379.83 ± 228.92 g in males; 2095.95 ± 145.49 in females), and endocranial capacity (1676.47 cm(3) ± 161.26 in males; 1476.48 ± 102.49 in females), but overlapping between sexes is quite significant. The average ECC in male (1676.5 cm(3)) and in female (1476.5 cm(3)) subjects is higher than those previously published, which deserves some discussion.     

Female and male sex offenders: a comparison of recidivism patterns and risk factors

Few studies have empirically validated the assertion that female and male sex offenders are vastly different. Therefore, utilizing a matched sample of 780 female and male sex offenders in New York State, the current study explored differences and similarities of recidivism patterns and risk factors for the two offender groups. Results suggested that male sex offenders were significantly more likely than female sex offenders to be rearrested for both sexual and nonsexual offenses. However, limited differences in terms of risk factors between female and male sex offenders were found.     

Sexual dimorphism in America: geometric morphometric analysis of the craniofacial region

One of the four pillars of the anthropological protocol is the estimation of sex. The protocol generally consists of linear metric analysis or visually assessing individual skeletal traits on the skull and pelvis based on an ordinal scale of 1-5, ranging from very masculine to very feminine. The morphologic traits are then some how averaged by the investigator to estimate sex. Some skulls may be misclassified because of apparent morphologic features that appear more or less robust due to size differences among individuals. The question of misclassification may be further exemplified in light of comparisons across populations that may differ not only in cranial robusticity but also in stature and general physique. The purpose of this study is to further examine the effect of size and sex on craniofacial shape among American populations to better understand the allometric foundation of skeletal traits currently used for sex estimation. Three-dimensional coordinates of 16 standard craniofacial landmarks were collected using a Microscribe-3DX digitizer. Data were collected for 118 American White and Black males and females from the W.M. Bass Donated Collection and the Forensic Data Bank. The MANCOVA procedure tested shape differences as a function of sex and size. Sex had a significant influence on shape for both American Whites (F = 2.90; d.f. = 19, 39; p > F = 0.0024) and Blacks (F = 2.81; d.f. = 19, 37; p > F = 0.0035), whereas size did not have a significant influence on shape in either Whites (F = 1.69; d.f. = 19, 39; p > F = 0.08) or Blacks (F = 1.09; d.f. = 19, 37; p > F = 0.40). Therefore, for each sex, individuals of various sizes were statistically the same shape. In other words, while significant differences were present between the size of males and females (males on average were larger), there was no size effect beyond that accounted for by sex differences in size. Moreover, the consistency between American groups is interesting as it suggests that population differences in sexual dimorphism may result more from human variation in size than allometric variation in craniofacial morphology.     

A comparison of the neuropsychological profiles of adult male sex offenders and non-offenders with a learning disability

Abstract

The present study compared the neumpsychologlcal pmfiles of a group of adult male sex offenden with a laming disability (n-42) with a group of adult male non-offenders with a learning disability (n-42) using the Wechsler Adult Intelligence Scale - Revised (1986). The groups wen matched for full-scale IQ. Thc study found that the non-offender group had significantly higher Verbal 1Q scorn than the sex offender group. No significant differences wen found for Performance IQ. The non-ofinder group was also found to have significantly hlgher scores on the Vocabulary sub-test than the sex offender group and the sex offender group was found to have significantly higher scores on the ObJecr Assembly subtest than the non-ofinder group. Finally. the sex offender group was found to have a significantly lower Verbal IQ than Performance IQ. No significant Verbal-Performance discrepancy was found for the non-offender group. Possible implications of these findings are dlscusscd.     

Technics for postmortem removal of inner ear fluid

Two methods for sampling inner ear fluid (a mixture of endolymph and perilymph) from corpses are described and compared. Using the classical method, a part of the petrous bone is chiselled out and, subsequently, a needle, attached to a 1-ml-syringe, is inserted through the oval foramen into the region of the utriculus. The inner ear fluid can then be removed. When the method proposed by Trela (1975) is applied, thin layers of the petrous crest are chiselled out until the common crus of the superior and posterior semi-circular becomes apparent. With a needle, attached to a 1-ml-syringe, the inner ear fluid can then be collected. The experiments show Trela's method to be simpler than the classical method. Moreover, only small amounts of inner ear fluid can be obtained by the latter technique. Trela's method is recommended for further studies on this fluid, which may be of forensic interest.