Comparative analysis of four morphometric methods for sex estimation: A study conducted on human skulls.

The pelvis and skull are the regions of the human skeleton that most clearly show sexual dimorphism, with the pelvis being superior to the skull for sex estimation owing to reproductive and hormonal factors. However, as many skeletons are found incomplete, it is important to be able to determine sex from analyzing the skull as well as the pelvis. This study was aimed at validating and evaluating the effectiveness of four morphometric methods for sex estimation using the human skull. One hundred human Brazilian skulls belonging to identified but unclaimed skeletons were used after all legal and administrative requirements for exhumation were satisfied. Four dimensions were analyzed: the facial triangle; the bimastoid triangle; the mastoid triangle; and finally, the occipital triangle. These dimensions were used to calculate the triangle areas. Descriptive analysis was used to verify the mean, standard deviation, and confidence interval of all variables and discriminant analysis with cross-validation was used to verify the percentage of correctness of the sex estimation methods. Individual analysis of the areas of the facial, right mastoid, left mastoid, bimastoid, and occipital triangles, and sum of the mastoid triangle areas, produced average accuracies of 63.0%, 81.8%, 77.8%, 71.4%, 64.0%, and 80.8%, respectively. Combinations of triangles resulted in higher mean accuracy percentages, with only 75.6% accuracy recorded when the left and right mastoid triangle areas were removed. All average values of analyzed triangles were higher in males than in females. Analyses of the cranial triangles were useful for sex estimation in the population studied.

Discriminant analysis of mandibular measurements for the estimation of sex in a modern Brazilian sample.

The present study aimed to evaluate the accuracy of mandibular measurements for sex determination in a Brazilian population. The sample was composed of 100 mandibles, of which 53 were female and 47 were male, and the average age was 57.03 years. The mandible measurement protocol was composed of 15 measurements, of which six were bilateral and nine were unique. Mandibles were directly measured using a digital caliper and a protractor. The descriptive analysis of the present study revealed higher mean values for male mandibles compared to those for female mandibles with the exception of the left mandibular angle. Among the 21 measures analyzed in this group, 15 were statistically significant (p < 0.05). Univariate discriminant analyses produced a mean percentage of correct predictions that varied between 49 and 79%. The association of variables increased the percentage of correct prediction of sex to vary from 76 to 86%. The receiver operator characteristic (ROC) curve analysis indicated that the best variable for estimating sex was bigonial breadth (BGB; area under the ROC curve (AUC) = 0.764) followed by the right maximum ramus height (MRHr; AUC = 0.763). A reference table for estimating sex in a Brazilian population using mandible measurements was developed based on the ROC curve analysis. Mandibular measures provide a simple and reliable method for sex discrimination in Brazilian adults due to the sexual dimorphism revealed by analysis of the metric variables and the satisfactory results demonstrated by discriminant formulas, ROC curve analysis, and the reference table.

Facial soft tissue thickness in the Brazilian population: new reference data and anatomical landmarks.

Facial soft tissue thickness measurement can be useful among several medico-legal techniques that aim to establish the identity of skeletal remains. This study examined the soft tissue thickness that covered the faces of autopsied cadavers sent to the Medico-Legal Institute of Guarulhos from September 2010 to September 2011. Forty-nine anatomical facial landmarks were measured in cadavers less than 24h after death; these data were analysed using two-tailed t-tests. This project was approved by an ethics committee. One hundred cadavers were studied (74 males and 26 females). A majority of these individuals had died between 41 and 60 years old. Of the 49 anatomical landmarks, only five differed between the sexes (i.e., p-value less than 0.05): upper lip margin (p=0.006), superior labial sulcus (p=0.006), stomion (p=0.001), right lateral orbit (p=0.008), and left cheilion (p=0.009). The inclusion of additional anatomical landmarks allowed us to establish more precise facial thickness parameters that have the potential to be applied to cadaver facial approximations in Brazil; furthermore, some anatomic landmarks presented a higher discriminant power with regard to sex.

Facial soft tissue thickness of Brazilian adults.

The auxiliary technique known as Facial Reconstruction enables one to reestablish the contours of the soft tissues over the skull, therefore producing a face and increasing the probability of a facial recognition. The reliability of this technique depends on the evaluation of the mean values of soft tissue thicknesses observed in a given population. Measurements were evaluated in autopsied corpses in "Section of Technical Verification of Deaths" in Guarulhos, São Paulo, Brazil. Thickness was measured manually by puncturing 10 midline craniometrical points and 11 bilateral points on a sample of 40 corpses of both sexes aged between 17 and 90 years, classified by skin color and the nutritional state. The results for the average thickness values are higher for males, variations related to the nutritional state are proportional to the increased fat on the face and age was not significant. The ethnic variable related to skin color when compared to studies with other populations showed differences, with the need for a reference table for a given population application of Facial Reconstruction technique in skulls of non-attributable identity.

Sexing the human skull through the mastoid process.

OBJECTIVE: The purpose of this study was to evaluate the significance for sex determination of the measurement of the area formed by the xerographic projection of 3 craniometric points related to the mastoid process: the porion, asterion, and mastoidale points. METHOD: Sixty skulls, 30 male and 30 female, were analyzed. A xerographic copy of each side of the skull was obtained. On each xerographic copy, the craniometric points were marked to demarcate a triangle. The area (mm ) of the demarcated triangle for each side of the skull (right (D) and left (E) sides) was determined, and the total value of these measures (T) was calculated. RESULTS: Concerning the right area of the male and female skulls, 60% of the values overlapped; for the left area, 51.67% overlapped, and for the total area, 36.67% overlapped. The analysis of the differences between the sexes in the areas studied was significant for the 3 areas. Regarding the total area, which is the preferred measurement because of the asymmetry between the sides of the skull, the value of the mean was 1505.32 mm for male skulls, which was greater than the maximum value obtained in the female skulls. The value of the mean for female skulls was 1221.24 mm , less than the minimum value obtained for the male skulls. CONCLUSIONS: This study demonstrates a significant result in the 3 studied areas, (D), (E), and (T). The total area values show less overlapping of values between the sexes, and therefore can be used for sexing human skulls. For the population studied, values of the total area that were greater than or equal to 1447.40 mm belonged to male crania (95% confidence). Values for this area that were less than or equal to 1260.36 mm belonged to female crania (95% confidence).