In this dissertation I evaluate the potential of the morphology of the
petrous portion of the human temporal bone as seen on axial CT scans of the
head as a means to generate identifications of fragmentary human skeletal
remains. The specific goals are threefold: (1) To investigate variability in the
shape of the petrous portion of the human temporal bone using two-dimensional
morphometric analysis; (2) to evaluate the reliability of the resultant method in
forensic identification; and (3) to consider the results within the framework of
Bayesian theory in light of recent rulings regarding the admissibility of forensic
testimony.
The data used in this research were collected from axial CT images of the
cranium. Two sets of images were collected for each of the 115 individuals in
the sample so that Euclidean distance comparisons could be made between
images of the same individual and images from different individuals. I collected two-dimensional coordinate data from 36 landmarks on each of the CT images
and calculated the distances between each of the coordinate points to generate
the data used in the statistical analyses.
I pared down this set of measurements using two different models
(referred to as the biological and PCFA models). The measurement sets of both
models were then compared to one another using nearest neighbor analysis, to
test their relative efficiency in matching replicate images to one another. The
results of both models were highly accurate. Three incorrect nearest neighbor
matches resulted from the biological model and 5 from the PCFA model. The
errors appear to have been the result of variation in the axial plane between the
first and second scans.
The results of the nearest neighbor comparisons were then considered
within the context of Bayes' Theorem by calculating likelihood ratios and
posterior probabilities. The likelihood ratios and posterior probabilities were very
high for both models, indicating that: 1) there is significant individual variability in
the measurements of the petrous portion used in this research, and 2) this
variation represents a high level of potential accuracy in the application of this
method in the identification of forensic remains.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1724 |
| Date | 02 June 2009 |
| Creators | Wiersema, Jason Matthew |
| Contributors | Wright, Lori E. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
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