Tumbling abrasions. Injuries from ricocheting bullets

Atypical entrance gunshot wounds may be produced by deflected or ricocheting bullets. One special type of atypical entrance wound involves abrasion of the skin at a site that is remote from the point of dermal penetration. These remote abrasions, termed "tumbling abrasions," are produced by bullets that tumble after impact with an intermediate target. Three cases of tumbling abrasions are presented.     

Use of the global positioning system in the field recovery of scattered human remains

This study examines the Global Positioning System (GPS) as a tool for field mapping of scattered human remains or other materials in forensic investigations. Two aspects of the GPS are considered: (1) the level of accuracy that can be obtained using a mid-priced GPS unit, and (2) the effectiveness of using the GPS to map scattered materials. The positional accuracy of the GPS receiver was tested using a National Geodetic Survey (NGS) point located in Baton Rouge, LA. The utility of the GPS for mapping was investigated by setting up a mock field recovery and mapping the remains using both the GPS and traditional archeological methods. The results indicate that the positional error for a single location using GPS was less than one-half meter. However, when multiple positions were considered, the data produced on different days were not consistent. Further, the GPS receiver used in this study could not distinguish items in close association. Factors such as tree cover density, the proximity of the materials to structures or trees, and satellite positioning contributed to the erratic data. These results indicate that traditional techniques and photographs are still indispensable for mapping scattered remains or artifacts.     

Nursing home deaths which fall under the jurisdiction of the coroner: an 11-year retrospective study

Twenty percent of deaths in the United States occur in nursing homes, yet less than 1% come to autopsy. The current study analyzed causes and manners of death in all nursing homes between 1993 and 2003, investigated by the coroner of Allegheny County, PA, which has the second highest elderly population in the United States. Two hundred eight decedents were identified, aged 19 to 91 years, 58% women and 42% men, 88% Caucasian and 22% African-American. Fifty-eight percent were accidental and 38.5% were natural manners of death, with 2 homicides, 2 suicides, and 3 undetermined cases. The manner of death was significantly different between Caucasians and African-Americans, with 92.6% of accidental deaths occurring in Caucasians and 6.6% in African-Americans (P < 0.1). Most common natural deaths were arteriosclerotic cardiovascular disease, nonarteriosclerotic cardiovascular disease, pneumonia, pulmonary thromboembolism, chronic obstructive pulmonary disease (COPD), seizure disorder, and atraumatic intracranial hemorrhage. Blunt force trauma was the single most commonly identified traumatic accidental death. Accidental deaths were more common in Caucasians than African-Americans. Homicides and suicides were rare events (<2%). Blunt force trauma is a major autopsy finding in accidental nursing home deaths, and a root-cause analysis may be helpful in developing policies and procedures to decrease the incidence of blunt force trauma.     

Patella sex determination by 3D statistical shape models and nonlinear classifiers

Sex determination is one of the essential steps in personal identification of an individual from skeletal remains. Most elements of the skeleton have been subjected to discriminant function analysis for sex estimation, but little work has been done in terms of the patella. This paper proposes a new sex determination method from the patella using a novel automated feature extraction technique. A dataset of 228 patellae (95 females and 133 males) was amassed from the William M. Bass Donated Skeletal Collection from the University of Tennessee and was subjected to noninvasive high resolution computed tomography (CT). After the CT data were segmented, a set of features was automatically extracted, normalized, and ranked. The segmentation process with surface smoothing minimizes the noise from enthesophytes and ultimately allows our methods to distinguish variations in patellar morphology. These features include geometric features, moments, principal axes, and principal components. A feature vector of dimension 45 for each subject was then constructed. A set of statistical and supervised neural network classification methods were used to classify the sex of the patellar feature vectors. Nonlinear classifiers such as neural networks have been used in previous research to analyze several medical diagnosis problems, including quantitative tissue characterization and automated chromosome classification. In this paper, different classification methods were compared. Classification success ranged from 83.77% average classification rate using labels from a Fuzzy C-Means (FCM) clustering step, to 90.3% for linear discriminant classification (LDC). We obtained results of 96.02% and 93.51% training and testing classification rates, respectively, using feed-forward backpropagation neural networks (NN). These promising results using newly developed features and the application of nonlinear classifiers encourage the usage of these methods in forensic anthropology for identifying the sex of an individual from incomplete skeletons retaining at least one patella.