A comparative microscopic study of human and non-human long bone histology.

Identification of human or nonhuman skeletal remains is important in assisting the police \nand law enforcement officers for the investigation of forensic cases. Identification of bone \ncan be difficult, especially in fragmented remains. It has been reported that 25 to 30% of \nmedicolegal cases, which involved nonhuman skeletal remains have been mistaken for \nhuman. In such cases, histomorphometric method was used to identify human and \nnonhuman skeletal remains. However, literature has shown that histomorphometric data for \nhuman and nonhuman bone were insufficient. Additionally, age estimation in bone may \nhelp in the identification of human individual, which can be done by using a \nhistomorphometric method. Age estimation is based on bone remodeling process, where \nmicrostructural parameters have strong correlations with age. Literature showed that age \nestimation has been done on the American and European populations. However, little work \nhas been done in the Asian population. The aims of this project were thus, to identify \nhuman and nonhuman bone, and to estimate age in human bones by using \nhistomorphometric analysis. In this project, 64 human bones and 65 animal bones were \ncollected from the mortuary of the Universiti Kebangsaan Malaysia Medical Centre and the \nZoos in Malaysia, respectively. A standard bone preparation was used to prepare human \nand nonhuman bone thin sections for histomorphometric assessment. Assessments were \nmade on the microstructural parameters such as cortical thickness, medullary cavity \ndiameter, osteon count, osteon diameter, osteon area, osteon perimeter, Haversian canal \ndiameter, Haversian canal area, Haversian canal perimeter, and Haversian lamella count per \nosteon by using image analysis, and viewed under a transmitted light microscope. The \nmicrostructural measurements showed significant differences between human and \nnonhuman samples. The discriminant functions showed correct classification rates for \n81.4% of cases, and the accuracy of identification was 96.9% for human and 66.2% for \nanimal. Human age estimation showed a standard error of estimate of 10.41 years, \ncomparable with those in the literature. This study project offers distinct advantages over \ncurrently available histomorphometric methods for human and nonhuman identification and \nhuman age estimation. This will have significant implications in the assessment of \nfragmentary skeletal and forensic population samples for identification purposes.