Regional and Seasonal Effects on Long Bone Fracture Characteristics

Forensic anthropologists are often tasked with analyzing skeletal trauma to determine the timing of bone fractures. Differentiating between perimortem trauma and postmortem damage is especially complicated due to the variable timing of bone degradation and subsequent changes in fracture morphology. Different investigations into the timing at which bone fractures transition from wet to dry morphology have yielded varying results. One explanation may be related to exposure to different seasonal and regional climatic conditions, as studies have been conducted in diverse geographical locations and during different seasons. Alternatively, or in addition, differences may be attributed to methodological approaches used to describe and score fracture characteristics. This thesis explored the potential influences of fracture classification methods, regional environmental conditions, and seasonal environmental conditions on the transition of wet to dry bone fractures throughout the postmortem interval in West Texas. Blunt force impact experiments were conducted on deer femora exposed to outdoor conditions over two 14-week trials conducted during the winter-spring (January through May) and summer-fall (June through September) seasons in West Texas. In each trial, 35 deer femora were placed outdoors, and five bones were removed and fractured every two weeks. Four different methods were applied to score fracture angle, fracture outline, and fracture surface. Fractographic surface features including bone mirror, bone hackle, arrest ridge, wake feature, and cantilever curl were also assessed. Results obtained in the two West Texas trials were compared to assess seasonal differences. Subsequently, West Texas results were compared to previously published findings from Central Florida and Massachusetts to assess regional differences. Results indicate that method influences fracture angle, outline, and surface expression scores, as frequency distributions differed significantly based on the methodology employed. Additionally, exposure to regionally variable environmental conditions may also impact the frequency of both fracture characteristics and fractographic features. Strong, statistically significant differences were found between fractures obtained in West Texas and those obtained in Central Florida and Massachusetts when the same scoring methods were employed. Few differences in the frequency of fracture characteristics and fractographic features were found between trials conducted in different seasons in West Texas, however. This study provides baseline information on the relationships between fracture classification methods, regional and seasonal environmental conditions, and the transitions of wet to dry bone fracture characteristics. These results build upon the existing body of research focusing on the transition from wet to dry bone. The findings of this study can serve as a starting point for future investigations into the effects of regional and seasonal climatic conditions on fracture morphology throughout the postmortem period. Additionally, the results can inform future investigations regarding the influence of methodological approaches on trauma interpretations.

Name thesis:degree_name

Master of Arts

Discipline thesis:degree_discipline

Anthropology

Grantor

Texas Tech University

Year dc:date.issued

2024

Author dc:creator

• Unger, Carter

Chair dc:contributor.committeechair

• Isa, Mari

Committee member dc:contributor.committeemember

• Durband, Arthur

• Forensic Anthropology
• Postmortem Interval
• Blunt Force Trauma
• Fractography
• Environmental Effects
• Methodology

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/2346/99401

OAI identifier oai:identifier

oai:ttu-ir.tdl.org:2346/99401