Biomedical subjects

Tracy L Rogers

Publications and source records attributed to Tracy L Rogers.

6 recordsLinked to original sources

PubMed2007

Variation in cortical bone histology within the human femur and its impact on estimating age at death.

Histological methods for the estimation of age at death using cortical bone are based on the evaluation of microstructural changes over time. Since histological analysis is a destructive method, most techniques attempt to limit the amount of cortical bone needed for analysis. Sample location, however, can have a significant effect on the accuracy of these methods. Furthermore, research demonstrates that both intersection and intrasection variation is present at the midshaft of the femur, which is the primary location for estimating age at death in humans. This research determines the extent of regional variation within the adult human femur and its effect on age estimation. Secondary osteon lamellae and Haversian canal ratio and cortical thickness were quantified. Thompson's All Males Left Femur regression equation was used to estimate age. Results show that significant regional variation occurs in the estimated ages derived from the posterior aspect of the femoral shaft and significant intrasection variation occurs in age estimates from the mid and mid-distal cross-sections. Thus, the inter and intrasection variation that occurs in bone remodeling within the femoral cortex has the potential to produce significant differences amongst age estimates taken from various femoral diaphyseal locations compared to the age estimated from the standard location used in Thompson's core method (1978). The results indicate that the use of this histological method is dependant on the ability to correctly identify the four anatomical locations, but the extracted core used for age estimation is not necessarily confined to the anterior midshaft.

Age Determination by Skeleton↗

PubMed2005

Recognition of cemetery remains in a forensic context.

The purpose of this paper is to provide guidelines for the recognition of human remains from modem and historic cemeteries found in a forensic context. Three avenues of evidence may be pursued to confirm the origin of cemetery remains: context, condition of the body, and associated artifacts. This article outlines types of North American cemeteries, demonstrating how land use over time has resulted in many being closed, moved, or forgotten, leaving only the context to indicate their presence. The condition of human cemetery remains varies considerably depending on cultural practices and burial environment, but many exhibit combinations of the following traits: dried or embalmed tissue; erosion of bony pressure points; cortical bone flaking; and bone damage due to autopsy or embalming. Examples of artifact types useful in recognizing cemetery remains are also provided. Two cases from British Columbia, Canada are presented to demonstrate the diagnostic features of a disturbed cemetery burial.

Autopsy↗

PubMed2005

Determining the sex of human remains through cranial morphology.

Sex determination is the keystone of a biological profile, yet few qualitative methods of cranial sex determination have been tested. This analysis examines the accuracy and precision of 17 morphological features of the skull commonly used to determine the sex of unknown skeletal remains. The sample consists of 46 identified skulls from the 19th century St. Thomas' Anglican Church Cemetery in Belleville, Canada. Nasal aperature, zygomatic extension, malar size/rugosity, and supraorbital ridge proved the most useful; of secondary value are chin form and nuchal crest; mastoid size is of tertiary consideration; nasal size and mandibular symphysis/ramus size rank fourth; forehead shape ranks fifth; and palate size/shape are sixth. Skull size/architecture provides an internal standard to assess the relative sizes of other traits. This research is a necessary step in establishing the credibility of morphological sex determination with respect to the Daubert and Mohan criteria for admissibility in a court of law.

Cephalometry↗

PubMed2004

Expert testimony and positive identification of human remains through cranial suture patterns.

North American forensic anthropological research should conform to the Daubert criteria (U.S.A.) and Mohan ruling (Canada) to ensure admissibility in a court of law. Positive identification through radiographic comparison of antemortem and postmortem cranial suture patterns was evaluated in light of these criteria. The technique is based on reliable principles, but problems with terminology and the resolution of radiographs make Sekharan's method difficult to apply. Using the location, length, and slope of a suture's component lines, rather than Sekharan's descriptions of sutural configurations, it is possible to determine the probability of a particular suture pattern occurring in more than one individual. A match of four consecutive lines is sufficient to establish positive identification. This approach meets the Daubert and Mohan criteria, although resolution of radiographs is still a major limitation. Computed tomography (CT) scans may prove a more useful modality for positive identification, due to better resolution and greater availability.

Anthropometry↗

PubMed2004

Crime scene ethics: souvenirs, teaching material, and artifacts.

Police and forensic specialists are ethically obliged to preserve the integrity of their investigations and their agencies' reputations. The American Academy of Forensic Sciences and the Canadian Society of Forensic Science provide no guidelines for crime scene ethics, or the retention of items from former crime scenes. Guidelines are necessary to define acceptable behavior relating to removing, keeping, or selling artifacts, souvenirs, or teaching specimens from former crime scenes, where such activities are not illegal, to prevent potential conflicts of interest and the appearance of impropriety. Proposed guidelines permit the retention of objects with educational value, provided they are not of significance to the case, they are not removed until the scene is released, permission has been obtained from the property owner and police investigator, and the item has no significant monetary value. Permission is necessary even if objects appear discarded, or are not typically regarded as property, e.g., animal bones.

Canada↗

PubMed2002

Identifying chop marks on cremated bone: a preliminary study.

The purpose of this analysis is to evaluate the effects of burning on hacking trauma inflicted with a cleaver and to assess the diagnostic potential of cleaver marks exposed to fire. Thirty pig forelimbs (radius and ulna) and 30 beef ribs were each subjected to five blows with a cleaver and five cuts with a knife prior to burning in an outdoor fire. Bones were deliberately agitated to ensure maximum cremation and induce fragmentation. Results indicate that hacking weakens bone, making fire-induced fragmentation more likely at the sites of trauma. Chop marks were easily identified on burned bone, their characteristics largely unaffected by cremation.

Animals↗