A quantitative assessment of Saw Kerf floor shape patterns using outline analysis

Area of Science:

• Forensic Anthropology
• Bioarchaeology
• Forensic Science

Background:

• Forensic anthropologists analyze bone cut surfaces to identify saw marks in dismemberment cases.
• Previous methods relied on subjective visual analysis of saw marks, limiting statistical rigor.
• Understanding saw characteristics aids legal and investigative proceedings.

Purpose of the Study:

• To quantitatively assess the relationship between kerf (saw cut) shapes and saw class characteristics using elliptical Fourier analysis.
• To establish objective, statistically supported methods for analyzing saw marks in forensic anthropology.
• To improve the accuracy of identifying saw type, power, and tooth shape from bone evidence.

Main Methods:

• 133 incomplete kerf profiles from 19 different saws were analyzed.
• Kerf profiles were captured using a stereomicroscope and analyzed with elliptical Fourier and principal component analyses.
• Statistical analyses (PerMANOVAs, Kruskal-Wallis, DFA) were used to correlate kerf shape with saw characteristics (set, power, tooth shape).

Main Results:

• Elliptical Fourier analysis provided quantitative data on kerf shapes.
• Discriminant function analysis achieved 88.0% accuracy in classifying tooth shape and 89.5% accuracy in classifying saw power.
• Specific kerf shapes (flat, U, W) were associated with rip and crosscut saws; mechanical saws produced wider kerfs than hand saws.

Conclusions:

• Quantitative analysis of kerf shapes using elliptical Fourier analysis supports and refines existing anecdotal relationships in forensic anthropology.
• This objective methodology enhances the reliability of identifying saw characteristics from bone evidence.
• The findings contribute to more accurate and legally defensible assessments in forensic investigations involving dismemberment.