Quantifying cortical bone in fragmentary archeological second metacarpals

Area of Science:

• Bioarchaeology
• Paleopathology
• Forensic Anthropology

Background:

• Cortical bone thickness indicates skeletal health and quality in archaeological populations.
• Traditional methods for measuring bone loss in second metacarpals require complete elements, limiting sample size and potentially biasing results.
• Fragmentary skeletal remains are often excluded, hindering comprehensive analysis of bone acquisition and loss patterns.

Purpose of the Study:

• Introduce and validate a novel "Region of Interest" (ROI) method for quantifying cortical bone in second metacarpals.
• Overcome limitations of traditional radiogrammetry that exclude incomplete skeletal elements.
• Enhance the ability to study bone quality and age-related bone loss in archaeological assemblages.

Main Methods:

• Adapted the "Region of Interest" (ROI) method from digital X-ray radiogrammetry (DXR).
• Quantified cortical bone area within a standardized 1.9 cm mid-diaphyseal region of second metacarpals.
• Standardized measurements for body size using total area (Cortical Area Index ROI - CAI_ROI) and compared to traditional cortical indices (CI).

Main Results:

• The ROI method demonstrated high intra- and interobserver reliability.
• CAI_ROI values showed strong and significant correlations with traditional CI values in both males (r=0.906) and females (r=0.925).
• The method effectively quantifies bone in archeological remains with suboptimal preservation.

Conclusions:

• The ROI method is a reliable complement to traditional radiogrammetry for analyzing cortical bone.
• This technique maximizes sample sizes by including incomplete second metacarpals.
• Enables more comprehensive depictions of bone acquisition and loss patterns in archaeological studies.