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%.     

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.     

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。     

Course of the meatus acusticus internus as criterion for sex differentiation

The importance of features that allow the determination of an individual's gender even with skulls that have been largely destroyed is undisputed in archaeological and anthropological practice. Due to its extreme mechanical strength, the pars petrosa ossis temporalis is usually preserved in skulls and the sex dimorphisms of this skeletal part are therefore of particular significance. In the present study, we aimed at clarifying the controversial question whether the course of the meatus acusticus internus (M.a.i.) beneath the superior surface also reveals sex-specific differences. Using 410 forensically modern petrous portions, the course of the canal was examined and the respective angles determined using a specifically developed casting and cutting technique. The median values certainly reveal sex differences: the lateral angle on the male petrous portions is 10 degrees smaller than that of females; the medial angles on female petrous portions are approximately 5 degrees smaller than those of male skulls. Using discriminant analysis, approximately 66% of the specimens can be determined accurately.     

Palatine Sutures as Age Indicator: A Controlled Study in the Elderly

Abstract:  Vault sutures have proven their low reliability for estimating age at death in individual forensic science cases. We broke down the palatine sutures of 134 skulls (with known sex and age at time of death) into 15 subparts and 5 stages of fusion to obtain a mean coefficient of obliteration ( C p) which was then linked to five age classes. We completed this study with multiple regression equations of total palatine suture scores. We compared our results with those obtained using the Mann method on the one hand and classically segmented and scored ectocranial suture age determination methods on the other. Palatine sutures generally do not estimate age at death any better than cranial vault sutures. Despite the partly subjective aspect of suture study, palatine suture observation contributes additional information to age-range estimation, especially in old and very old subjects where other methods lose their effectiveness.     

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。     

Determination of sex from femora

The determination of sex from bones or bone fragments considerably contributes to identifying unknown bodies or skeletal remains. Due to temporal change and regional differences anthropometric standards have to be constantly renewed. The present study provides measurements of femoral dimensions in a contemporary German population and analyses sexual dimorphism by discriminant analysis. Maximum length (male: 46.4+/-2.4 cm, female: 43.4+/-2.4 cm), maximum midshaft diameter (male: 3.1+/-0.2 cm, female: 2.8+/-0.2 cm), condylar width (male: 8.4+/-1.0 cm, female: 7.7+/-0.5 cm), vertical head diameter (male: 4.9+/-0.3 cm, female: 4.4+/-0.3 cm), head circumference (male: 15.7+/-0.8 cm, female: 13.8+/-1.0 cm) and transverse head diameter (male: 4.9+/-0.3 cm, female: 4.3+/-0.3 cm) were measured in 170 femora, 100 from male (age: 16-92 years, mean: 60.8 years; body height: 153-190 cm, mean: 171 cm) and 70 from female (age: 20-96 years, mean: 72 years; body height: 146-175 cm, mean: 161 cm) individuals. In the discriminant analysis (leave-one-out-method) 67.7% of cases could be grouped correctly with the maximum length alone, 72.4% with the maximum midshaft diameter, 81.4% with the condylar width, 86.8% with the vertical head diameter, 87.7% with the head circumference and 89.6% with the transverse head diameter. The stepwise procedure with all head measurements showed that the results for the transverse head diameter could not be improved. With all measurements subjected to stepwise procedure 91.7% of cases could be classified correctly combining midshaft diameter and head circumference (D=3.012xmidshaft diameter in cm+0.780xhead circumference in cm 20.569).     

Sex determination with the head of the radius

Analysis of a sample of 1108 radii corresponding to 567 black and white North Americans in the Terry Collection at the Smithsonian Institution demonstrates that the diameter of the radial head is an accurate sex discriminator for human remains. A simple "radial-head method" of sex determination consists of measuring the maximum and minimum diameters of the head and comparing such measurements with the test cutoff points. The subject is female when the maximum radial head diameter (either left or right) is less than or equal to 21 mm, and male when the maximum diameter (either left or right) is greater than or equal to 24 mm. The same decisions apply to the minimum diameters of 20 mm or less and 23 mm or more, respectively. When the maximum diameter is 23 mm or the minimum is 22 mm, the subject is more likely male; when the maximum diameter is 22 mm or the minimum is 21 mm, the subject is more likely female. The sample frequency of any one of these latter diameters is never more than 16%. Cross-validation of the method with a sample of 50 pairs of radii of the Terry Collection, different from the original specimens, resulted in 92% sexing accuracy when using the left radius singly, 94% accuracy when using the right radius singly, and 96% accuracy when using both radii jointly.     

Sex determination from plucked human hairs without epithelial root sheath

For sex determination, it is difficult to examine the sex chromatin in the hair root devoid of the epithelial root sheath because of melanin deposition in the hair cortex cells. In the present study, the possibility of determining sex was sought by observing the frequency of Y chromatin in the nuclei of hair cortex cells from human hair root devoid of epithelial root sheath. The male hair contained nuclei in each of which one brightly fluorescent spot was recognizable. The average frequency of the fluorescent spot in the hair cortex nuclei observed in 90 samples from 30 males was 59.4%; the maximum frequency was 74% and the minimum 37%. On the other hand, the fluorescent spots were rarely found in the nuclei of hair cortex cells from female hair. The frequency of occurrence was 5.3% on average, the maximum frequency being 12%, the minimum 0%. The frequency distribution of the male group and female group exhibited two discontinuous peaks. The frequency of the fluorescent spots can therefore be used as a criterion for determining sex. The fluorescent spot in dried male hair was shown to be detectable in a frequency of 20 – 40% 4 weeks after plucking, indicating that the nuclei of hair cortex cells can be subjected to the examination for at least this period if the hair has been kept in a dry condition.     

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.     

Humeral and femoral head diameters in recent white American skeletons

Osteologists often rely on single measurements, such as humeral and femoral head diameters, to estimate sex, especially when skeletons are incomplete. Measurements of 237 Bass Donated Collection skeletons provide a means of distinguishing white American females from males based on a modern sample: humeral head, female mean 42.1 mm, male mean 49.0 mm; and femoral head, female mean 42.2 mm, male mean 48.4 mm. Probabilities that bones at 1-mm increments came from females (p(f)) are estimated (p(m) = 1 - p(f)). An overrepresentation of one sex in the skeletons that are examined influences the probability that a bone of a certain size is from a female or male. So, probabilities are also estimated for samples consisting of an unequal number of males and females. Sample composition has its greatest effect when one sex dominates the remains that are the subject of investigation.     

Metric determination of sex from the humerus in a Guatemalan forensic sample

The absence of population-specific standards for sex, age and stature estimation for rural Guatemala is problematic for the forensic analysis of skeletal remains recovered from clandestine graves attributed to the recent armed conflict in that country. In order to increase the reliability of the forensic analyses being undertaken in Guatemala, standards for metric determination of sex were developed. Data was collected on several bones; the results for the humerus are presented here. A sample of 118 complete humeri (68 male and 50 female) was studied; maximum length, maximum diameter of the head, circumference at midshaft, maximum diameter at midshaft, minimum diameter at midshaft and epicondylar breadth were measured and subjected to discriminant function analysis. The classification accuracies for the univariate functions range from 76.8% for the maximum diameter at midshaft to 95.5% for the maximum diameter of the head. The classification accuracy for the stepwise procedure was 98.2%.     

Reliability of Craniofacial Superimposition Using Three‐Dimension Skull Model

Craniofacial superimposition is a technique potentially useful for the identification of unidentified human remains if a photo of the missing person is available. We have tested the reliability of the 2D‐3D computer‐aided nonautomatic superimposition techniques. Three‐dimension laser scans of five skulls and ten photographs were overlaid with an imaging software. The resulting superimpositions were evaluated using three methods: craniofacial landmarks, morphological features, and a combination of the two. A 3D model of each skull without its mandible was tested for superimposition; we also evaluated whether separating skulls by sex would increase correct identifications. Results show that the landmark method employing the entire skull is the more reliable one (5/5 correct identifications, 40% false positives [FP]), regardless of sex. However, the persistence of a high percentage of FP in all the methods evaluated indicates that these methods are unreliable for positive identification although the landmark‐only method could be useful for exclusion.     

Forensic Age-at-Death Estimation from the Human Sacrum*

Abstract: A new method is described here that incorporates seven developmental and degenerative changes for estimating chronological age from morphological features of the human sacrum. The construction of this method involved multiple stages of trait identification, character-state definition and age correlation, rank-order phase development, and percent-correct sample testing with phase and sample aggregation, all of which resulted in a six-phase component system for application on modern individuals. This phase system was first developed on European American male and female samples from the Hamann-Todd collection; then tested on African American male and female Hamann-Todd samples as well as European American male and females from the WM Bass collection to examine possible sex and/or ancestry differences. Variation in age estimates due to sex and ancestry was negligible; thus, the multiple samples were all pooled creating a robust method with a large sample size. Overall age ranges increase in width at two standard deviations as is expected from degenerative age-related processes but retain utility in forensic situations.     

Comparative analysis of differences by gender in sudden infant death syndrome in Hungary and Japan

We examined the sex ratio in sudden infant death syndrome (SIDS) cases in Hungary, in Tokyo and Japan between 1985 and 1996. From all the infant death cases in Hungary 395 (240 male, 155 female) were SIDS (odds ratio (OR)=1.179, with 95% confidence interval (CI)=0.961, 1.446), in Japan 4348 (2550 male, 1798 female) were SIDS (OR=1.145, with 95% CI=1.076, 1.218) and in Tokyo 307 (178 male, 129 female) were SIDS (OR=1.128, with 95% CI=0.894, 1.423). Male infants showed a significantly higher birth rate than females. The male infants are more vulnerable (p<0.005), however, higher mortality among male infants should not be considered a characteristic feature for SIDS.     

Stature and sex estimate using foot and shoe dimensions

The aim of the study was to develop a formula to estimate the stature and sex of an individual using foot and shoe dimensions. To this aim the stature, right and left shoe sizes, and maximum and minimum feet length and width measurements of a target group of 569 individuals were taken. The group was composed of 294 males and 275 females. The highest correlation coefficient was found in length measurements. A notable difference between males and females existed with regard to both right and left foot and shoe length and width averages and shoe sizes (p < 0.001). Among the group, a significant correlation was found in regard to stature and right shoe length (r = 0.591, p < 0.001), with the correlation between stature and right foot length and stature and right shoe length being 0.579 (p < 0.001); as for the female group, there was a significant correlation between stature and right foot length and stature and right shoe length (r = 0.460, p < 0.001). Thus the regression formula obtained are as follows: for the right side: sex = 69.169 + 0.173 (maximum foot length) - 0.368 (maximum foot width) - 0.820 (shoe length) + 0.224 (shoe width) - 1.280 (shoe number). For the left side: sex = 69.551 + 0.276 (maximum foot length) - 0.504 (maximum foot width) - 0.739 (shoe length) + 0.344 (shoe width) - 1.360 (shoe number). In application of the formula, if sex is lower than 0.50, the shoe belongs to a male, if higher, then to female. The formula which was obtained in regression analysis in order to estimate the stature when the measurements of shoe and foot were known. For the right side, stature = 47.93 + 1.083 (maximum foot length) + 0.788 (shoe length) 1.813 (shoe number) (SEE:31.410). For the left side: stature = 47.33 + 1.139 (maximum foot length) + 0.593 (shoe length) x 1.924 (shoe number) (SEE:31.607). It was understood that foot and shoe sizes are a criteria to estimate the stature of a person that there was a strong relationship between foot and shoe length and width and that these can be used to aid estimation. It was found that in sex estimate, foot and shoe lengths are better in helping the estimate than width measurements, and that the use of shoe measurements rather than bare foot measurements are better to obtain meaningful results.     

Identification of skull from its suture pattern

The examination of 320 skulls collected at random revealed that the ectocranial suture patterns in them are highly individualistic and that no two skulls can ever have an identical pattern. The possibility of these suture patterns being recorded incidentally in routine diagnostic skull radiographs was verified by examining the skull skiagrams preserved in radiology departments. A positive method of identification of the skull is suggested by the comparison of radiographic with visible skull suture pattern.     

Sexual Dimorphism in Auricular Surface Projection and Postauricular Sulcus Morphology

The presence of an elevated auricular surface and a postauricular sulcus is presented in numerous reference books as osteological indicators of sex, but the validity of these traits has not been adequately evaluated. The ilia of 322 (181 male, 141 female) adults were examined, the auricular surface was scored as completely, partially, or nonelevated, and the postauricular sulcus was scored as present or absent. Complete elevation occurred almost exclusively in females (67% of females and 0.6% of males). The postauricular sulcus was present in 27% of males and 85% of females. When present, an elevated auricular surface is a reliable indicator that the individual is female. However, the absence of the trait is a less reliable indicator of sex. The postauricular sulcus is a moderately accurate estimator of sex.     

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.     

Positive identification by a skull with multiple epigenetic traits and abnormal structure of the neurocranium, viscerocranium, and the skeleton

Wormian bones are small ossicles appearing within the cranial sutures in more than 40% of skulls, most commonly at the lambdoid suture and pterion. During the skeletal analysis of an unidentified male war victim, we observed multiple wormian bones and a patent metopic suture. Additionally, the right elbow was deformed, probably as a consequence of an old trauma. The skull was analyzed by cranial measurements and computerized tomography, revealing the presence of cranial deformities including hyperbrachicrania, localized reduction in hemispheral widths, increased cranial capacity, and sclerosis of the viscerocranium. Besides unique anatomical features and their anthropological value, such skeletal abnormalities also have a forensic value as the evidence to support the final identification of the victim.