Anthropological and radiographic comparison of vertebrae for identification of decomposed human remains

This case study demonstrates the importance of involving an anthropologist in forensic situations with decomposed remains. Anthropological consultation was used in conjunction with the comparison of antemortem and postmortem radiographs to establish positive identification of unknown, decomposed remains. The remains had no traditional identifying features such as fingerprints or dental. Through anthropological analysis, it was determined the decedent was male, between 20 and 23 years at time of death and c. 5'2' tall. This information allowed for a presumptive identification and a request for antemortem radiographs. The missing person was identified comparing the spinous processes of the cervical and thoracic vertebrae between ante- and postmortem radiographs.     

Positive Dental Identification Using Tooth Anatomy and Digital Superimposition

Dental identification of unknown human remains continues to be a relevant and reliable adjunct to forensic investigations. The advent of genomic and mitochondrial DNA procedures has not displaced the practical use of dental and related osseous structures remaining after destructive incidents that can render human remains unrecognizable, severely burned, and fragmented. The ability to conclusively identify victims of accident and homicide is based on the availability of antemortem records containing substantial and unambiguous proof of dental and related osseous characteristics. This case report documents the use of digital comparative analysis of antemortem dental models and postmortem dentition, to determine a dental identification. Images of dental models were digitally analyzed using Adobe Photoshop^TM software. Individual tooth anatomy was compared between the antemortem and postmortem images. Digital superimposition techniques were also used for the comparison. With the absence of antemortem radiographs, this method proved useful to reach a positive identification in this case.     

The Reliability of Visually Comparing Small Frontal Sinuses*

Abstract: Several studies have investigated frontal sinus comparison for personal identification. One study addressed the statistical reliability of correct identification using automated digital methods and resulted in a 96% accuracy rate. Missed matches with the digital methods generally involved small, less featured sinuses. This study investigates the hypothesis that human examiners may be able to more accurately identify correct matches than digital methods, even when the comparisons involve small frontal sinuses. Participants were provided two sets of 28 radiographs and were instructed to identify matching radiographs and list the radiographs that did not have a corresponding match. Overall, error rates were low, with correct associations identified at a rate of 0.983. No incorrect associations (“false positives”) were made. Correct association rates were highest among participants “experienced” examining radiographs. Results support previous assertions that frontal sinus radiographs are a reliable means of personal identification even when the frontal sinuses are small.     

Role of orthopedic implants and bone morphology in the identification of human remains

When conventional methods of identification, such as visual recognition and dental comparison, cannot be used to identify a deceased person, it becomes necessary to consider alternative methods. The presence of an orthopedic implant in a body may assist identification if ante-mortem medical records are available for comparison. Another method of identification involves comparison of ante-mortem and postmortem radiographs. Eight cases are reported from Forensic Science SA where the presence of orthopedic implants and/or ante-mortem radiographs were used to try to establish identification. In six cases, positive identification was established, and in two cases with upper limb orthopedic implants, the bones remained unidentified. Manufacturers were unable to provide any information about the distribution and use of the implants that could be of use with identification, as there are no requirements in Australia for individual medical implants to be tracked. Such a system has the potential to aid postmortem identification if serial codes were etched onto implants that could then be traced to manufacturers, surgeons, and recipients of these devices.     

Human Identification via Lateral Patella Radiographs: A Validation Study,

This research examines the utility of patella outline shape for matching 3D scans of patellae to knee radiographs using elliptical Fourier analysis and subjective methods of human visual comparison of patellae across radiographs for identification purposes. Repeat radiographs were captured of cadaver's knees for visual comparison before patellae were extracted and skeletonized for quantitative comparisons. Quantitative methods provided significant narrowing down of the candidate pool to just a few potential matches (<5% of original sample), while the human analysts showed high capacity for correctly matching radiographs, irrespective of educational level (positive predictive value = 99.8%). The successful computerized matching based on a single quantified patella trait (outline shape) helps explain the potency achieved by subjective visual examination. This work adds to a growing body of studies demonstrating the value of single isolated infracranial bones for human identification via radiographic comparison.     

Antemortem and Postmortem Nonapposite Data—A Multidisciplinary Identification Strategy

Identification of human remains is often achieved by comparing documented reference data with the same type of evidence obtained from the remains. We present a case of a decomposed unidentified body, whose identity was presumed but because of the low validity range of the available data, the identification process could not be completed. Antemortem radiographs of the teeth found in the house of the reputed victim could not be compared to the edentulous cadaver and the kinship between the victim and the only living relative that could provide DNA for comparison was too tenuous. Isolated teeth found at the scene, were neither a source of DNA reference information nor questioned data to be compared to the antemortem radiographs. The strategy implemented by the investigators to reallocate the status of the isolated teeth from the questioned source to the reference source of DNA to be compared with the cadaver is presented.     

Anthropological and Radiographic Comparison of Antemortem Surgical Records for Identification of Skeletal Remains*

Abstract: This case review illustrates the important contributions of forensic archeological methods and forensic anthropological analysis to the identification of found skeletal remains. After reassociation of skeletal remains found in two locations, anthropological analysis provided the basis for a presumptive identification and a request for antemortem medical records. Partial DNA profiles were supportive but not conclusive and antemortem dental records were not available. Comparison of antemortem traumas, skeletal morphology, and surgical artifacts with antemortem radiographs and surgical records led to positive identification of an individual missing for almost a decade.     

Personal identification based on radiographic vertebral features

Personal identification of human remains constitutes about 10% of the normal caseload of any forensic medicine practice. Identification can be achieved by a variety of methods, one of which is the comparison of antemortem and postmortem radiographs. There are numerous accounts of cranial and dental radiographic features useful for identification, whereas the availability of postcranial radiographs and especially plates that depict the vertebral column is less widespread among the forensic community. The authors here review the various vertebral features instrumental in positive identification that can be identified on radiographs of the spine.     

Prediction of stature based on radiographic measurements of cadaver long bones: a study of the Croatian population

We tested a new approach to the stature prediction that could be used in the identification process of human skeletal remains of unknown identity. The stature of 19 female and 21 male adult cadavers was measured within 24 h after death and considered to be equal to the living stature. The antero-posterior radiographs of all limbs were taken, and the maximum length of the six long bones was measured from radiographs. There was a significant difference in the stature and maximum length of long bones between female and male cadavers (p<0.001 for all). The correlation between the stature and long bone length was the best for the humerus in females (r=0.792) and the tibia in males (r=0.891). Regression equations specific to the Croatian population were computed separately for each long bone in males and females and proven to be reliable in predicting the living stature of the individual.     

Validation of chest X-ray comparisons for unknown decedent identification

Comparing skeletal structures between antemortem and postmortem chest radiographs is widely used by forensic specialists from many disciplines to positively identify unknown decedents. However, validity assessments of this method have been fairly limited. This study had three objectives: 1) to quantify the reliability of ante- and postmortem chest radiograph comparison for decedent identification; 2) to identify useful radiologic features supporting decedent identification; and 3) to recognize sources of error in decedent identification related to use of comparative radiographs. A forensic pathologist, a forensic anthropologist, and two radiologists participated in the study. Our results showed that chest radiograph comparisons proved reliable, if basic decedent information was provided, and antemortem and postmortem radiographs were adequately positioned and exposed. A "morphological approach" using normal anatomical structures for comparison may provide the most efficient method for accurate identification.     

Surgical Sutures as a Means of Identifying Human Remains*

Abstract: The Food and Drug Administration does not require surgical sutures to be tracked by manufacturer, physician, or patient; thereby, surgical sutures have been of little use to forensic practitioners who are tasked with establishing a positive identification with biological evidence. This study demonstrates the investigative process used to pinpoint suture manufacturers by presenting a case where surgical sutures were a distinctive characteristic that aided in the positive identification of skeletal remains. The suture’s manufacturer, construction material and structure, size, and medical use was determined by contacting a local surgical suture and orthopedic implant manufacturer and utilizing publicly available manufacturer websites, which provide catalogs and specific product details. This research was one of many lines of evidence used to establish the positive identification of a 47‐year‐old male.     

Root Morphology and Anatomical Patterns in Forensic Dental Identification: A Comparison of Computer‐Aided Identification with Traditional Forensic Dental Identification*

Abstract: An online forensic dental identification exercise was conducted involving 24 antemortem–postmortem (AM–PM) dental radiograph pairs from actual forensic identification cases. Images had been digitally cropped to remove coronal tooth structure and dental restorations. Volunteer forensic odontologists were passively recruited to compare the AM–PM dental radiographs online and conclude identification status using the guidelines for identification from the American Board of Forensic Odontology. The mean accuracy rate for identification was 86.0% (standard deviation 9.2%). The same radiograph pairs were compared using a digital imaging software algorithm, which generated a normalized coefficient of similarity for each pair. Twenty of the radiograph pairs generated a mean accuracy of 85.0%. Four of the pairs could not be used to generate a coefficient of similarity. Receiver operator curve and area under the curve statistical analysis confirmed good discrimination abilities of both methods (online exercise = 0.978; UT‐ID index = 0.923) and Spearman’s rank correlation coefficient analysis (0.683) indicated good correlation between the results of both methods. Computer‐aided dental identification allows for an objective comparison of AM–PM radiographs and can be a useful tool to support a forensic dental identification conclusion.     

A Reappraisal of Developing Deciduous Tooth Length as an Estimate of Age in Human Immature Skeletal Remains

This study provides an update on a quantitative method for immature age estimation based on postnatal deciduous mandibular tooth length. Two known sex and age skeletal collections from Western Europe were sampled (n = 97). Linear regression models for age estimated were calculated for each individual tooth, each sex, and sex combined sample using classical calibration. Prediction errors, residuals, and percentage of individuals whose real age fell within the 95% prediction interval were calculated. The teeth which develop earlier in life, the incisors and the first molar, showed the greatest precision, while the canine showed the least. This method has greater applicability to archeological skeletons or to children in developing countries than for use in North American or European forensic contexts. The method can be applied to incomplete or poorly preserved remains of unknown sex, particularly when dental radiographs are not an option or when teeth have been removed from the alveolus or crypt.     

Survival of Atherosclerotic Calcifications in Skeletonized Material: Forensic and Pathological Implications

Atherosclerosis is a chronic inflammatory disease creating calcifying plaques in the arterial walls. Because its paleopathological diagnosis remains little studied on skeletal remains, its impact on forensic and archeological data is completely underestimated. Here, 24 skeletal remains from the Milano Cemetery Skeletal Collection have been studied to evaluate the chance of atherosclerotic calcification survival, retrieval, and identification. Through direct comparison with a known autopsy collection and literature, the identification and categorization of several types of calcifications were performed. Clothing elements such as tights or socks played a definitive role in the preservation of the calcifications; hence they are more likely to be found in forensic cases than in archeological ones. Therefore, vascular calcifications are possible to collect and identify in skeletal remains if sufficient care is given to their recovery. Consequently and as markers of the disease, such identification can provide valuable pathological information for forensic and archeological cases.     

Identification Using Frontal Sinus by Three‐Dimensional Reconstruction from Computed Tomography*

Abstract: Radiographs and computed tomography (CT) images have been increasingly applied and accepted in forensic sciences. Along with radiographs and CT images, the frontal sinus is often used for the individual identification because of its unique and unchangeable characteristics. The purpose of this study is to define the usefulness of three‐dimensional (3‐D) images of the frontal sinus for identification. CT images from 119 Korean cadavers were built up for 3‐D reconstruction and surveyed with 15 measurements. The total volume of the sinus, some nonmetric characteristics, and the bilateral asymmetry index in men differed significantly from those in women (p < 0.05). The digit codes, six sections and 10‐digit number, were almost able to accurately identify individuals (98%). This study showed a statistical difference between the sexes and classified the fused and prominent middle sinuses for the first time. This proposed method for identification is more accurate than those used in other studies.     

Identification of Human Remains by DNA Analysis of the Gastrointestinal Contents of Fly Larvae

Dipterous fly larvae (maggots) are frequently collected from a corpse during a criminal investigation. Previous studies showed that DNA analysis of the gastrointestinal contents of maggots might be used to reveal the identity of a victim. However, this approach has not been used to date in legal investigations, and thus its practical usefulness is unknown. A badly burned body was discovered with its face and neck colonized by fly larvae. Given the condition of the body, identification was not possible. Short tandem repeat (STR) typing was performed using the gastrointestinal contents of maggots collected from the victim and was compared to STR profiles obtained from the alleged father. The probability of paternity was 99.685%. Thus, this comparative DNA test enabled the conclusive identification of the remains. This is the first reported case of analysis of human DNA isolated from the gastrointestinal tract of maggots used to identify a victim in a criminal case.     

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.     

Sex Determination from the Frontal Bone: A Geometric Morphometric Study

Sex estimation in human skeletal remains when using the cranium through traditional methods is a fundamental pillar in human identification; however, it may be possible to incur in a margin of error due because of the state of preservation in incomplete or fragmented remains. The aim of this investigation was sex estimation through the geometric morphometric analysis of the frontal bone. The sample employed 60 lateral radiographs of adult subjects of both sexes (30 males and 30 females), aged between 18 and 40 years, with mean age for males of 28 ± 4 and 30 ± 6 years for females. Thin‐plate splines evidenced strong expansion of the glabellar region in males and contraction in females. No significant differences were found between sexes with respect to size. The findings suggest differences in shape and size in the glabellar region, besides reaffirming the use of geometric morphometrics as a quantitative method in sex estimation.     

Skeletal identification by radiographic comparison: blind tests of a morphoscopic method using antemortem chest radiographs

This study investigated the value of antemortem (AM) and postmortem (PM) radiographs of the claviculae and C3-T4 vertebrae to identify skeletons of missing U.S. soldiers from past military operations. In total, 12 field-recovered skeletons and AM chest radiographs of 1460 individuals were used. For each skeleton, examiners analyzed an array of AM chest radiographs (up to 1000 individuals) and attempted to identify the correct PM/AM radiographic match. When examiners were able to compare all images within a single test, only true-positive identifications were made. When AM radiographs were presented one-at-a-time, in sequential order, and without examiners having knowledge of array size, erroneous identifications resulted but they were almost exclusively made by untrained examiners (accuracy = 35% vs. 90% for trained examiners). This study demonstrates the value of chest radiographs for the identification of disarticulated and even eroded skeletons, but only when methods are wielded by trained examiners.