The use of morphological features of the skull and mandible is a common approach used by anthropologists in sexing (Sweet 2001). A number of features are known to show variation between the sexes. The use of multiple features tends to be more accurate when used with young adults and the middle-aged. Williams and Rogers (2006) achieved 96% success in determining the sex using different features of the skull and the mandible. They also observed that using a constant six traits—mastoid, supraorbital ridge, size and architecture of skull, zygomatic extension, nasal aperture, and mandibular gonial angle—the accuracy was 94%. This indicates that craniofacial morphology can be used to determine the sex of skeletal specimen with a high degree of precision. The mandible is the largest and hardest facial bone and keeps its shape better than other bones in the forensic and dental anthropologic fields. It has been reported that of 13 nonmetric items of the mandible, the characteristic that best permitted the sexes to be distinguished was the contour of the lower border of the mandible: Rocker-shaped mandibles predominated in males (68.1%), whereas most females (84.6%) exhibited a straight mandible. In addition, the mental region was shaped differently between the sexes: The shape of the chin in most males was generally bilobate or square (91.7%), whereas the chin in females was either square (45.5%) or pointed (54.5%). In this study, the positive predictive values of male and female were 92.5% and 73.7%, respectively (Hu et al. 2006). Five variables were developed from the complete cranium, vault, face, mandible, and bizygomatic breadth. Dimensions from the complete cranium provided the best accuracy. In the mandible, bigonial breadth was the most dimorphic of the measurements taken. Average accuracies ranged from 80% (bizygomatic breadth alone) to 86% (cranium). Diagnostic accuracy, however, was lower than that obtained from the femur and tibia (Steyn and Iscan 1998). Rai et al. (2007) proposed that five BR criteria of sex determination from mandible parameters such as intercanine distance, intercondylar distance, interlingula (covering inferior alveolar foramen), mesiodistal diameter of mandibular canines, and mental foramen to lingula (covering inferior alveolar foramen). BR criteria for determination of sex reveal that the probability of male sex is 95% if three or more of the dimensions are greater than their deviation values. Krogman’s cranioscopy for sex determination is based on 14 characteristics of the skull (Table 5.1). On the other hand, a modified Krogman’s cranioscopy trait by grading was used to simplify gender classification since it was based on a four-point grade (i.e., 0, smooth; 1, small or rough; 2, medium or rougher; and 3, large or very rough) of only three external characteristics of the skull: supraorbital torus, glabella region, and external occipital protuberance (Krogman and Iscan 1986). These authors conducted a study to evaluate the sexual dimorphism in the cranium and mandible of North Indians using Krogman’s cranioscopy and the modified Krogman’s cranioscopy trait by ­grading (Table 5.2).

Teeth may be used for differentiating sex by measuring their mesiodistal (MD) and buccolingual (BL) dimensions. Various studies have shown significant differences between male and female permanent and deciduous tooth crown dimensions. In the majority of studies, the canines have consistently shown the maximum sex difference. It has been reported that sex can accurately be determined from maxillary and mandibular canines and mandibular second molar in 77% of cases (Is˛can and Kedici 2003). Canines showed the greatest univariate sex dimorphism, followed by the buccolingual (BL) dimension of maxillary first and second molars in Nepalese (Acharya and Mainali 2007). The mandibular canines are considered to demonstrate high sexual dimorphism among teeth in their mesiodistal width. Maxillary first molars (BL diameter), especially the right side, have a higher sexual dimorphism (8.49% casts, 8.27% intraorally) as compared to the left side and hence help in forensic dentistry during an impacted canine (Rai et al. 2008).

Rai et al. (2004) proposed a regression for sex determination from teeth as follows: Sex =1.528 (Maxillary central incisor B-L) – 1.322 (Premolar B-L) + 1.94 (Maxillary first molar B-L)-0.97 (Canine M-D) + 0.837 (Canine B-L)