Forensic ethnic identification of crania: the role of the maxillary sinus--a new approach.

Forensic pathologists may be asked to identify the ethnic group and gender of a cranium of unknown origin. An analysis of the maxillary sinus--its volume, shape, and dimensions in dried crania of different ethnic and gender groups (European and Zulu male and female)--was conducted to establish a new approach. A variation in maxillary sinus volume may mean a variation in anatomic landmarks between the groups. Ethnic and gender variations in the shape of the maxillary sinus of the crania were investigated. This research was further extended to predict the gender and ethnic group from an unknown cranium to make this research valuable to the fields of forensic pathology and anthropology. Helical, multislice computed tomography was performed using 1-mm coronal slices. The area for each slice was obtained by tracing the outline of each slice. The computed tomographic machine calculated a volume by totalling the slices for each sinus. Advanced computer methodology including a neural network was designed and applied to search for classification patterns in data. A discriminant analysis was performed to improve classification results. Ethnic and gender variations were found in the different groups, and the predictive role of the maxillary sinus in ethnic classification was established. It was found that European crania had significantly larger antral volumes than Zulu crania, and males had larger volumes than females. Dimensions of European sinuses were larger than those of Zulu sinuses. The medial antral wall of the sinus allowed for ethnic classification. The discriminant analysis allowed for a very successful 90% ethnic prediction, while gender prediction was ultimately 79%. The measurements taken and the formulae created in this research will be valuable to those in the field who are seeking to ethnically classify a cranium into one or another ethic group. This research aims to be an aid in identification, as well as a starting point for other scientific studies based on other ethnic groups. Perhaps its true value will lie in confirming ethnicity by adding to existing criteria. It must be noted that this classification is based on actual measurements and therefore eliminates the some of the subjectivity present in current methods of ethnic classification.