A Comparison of Postmortem and Perimortem Rib Fracture Patterns in Articulated and Disarticulated Ribs

Research on human bones has implications for multiple fields. Bone, or osteological, studies within anthropology often draw on outside disciplines in order to achieve a holistic understanding. Though the rib cage is a vital protective and structural component of the human body, ribs have undergone limited examination in regards to trauma or biomechanical properties with even fewer studies occurring on rib cages as a whole unit.

Both biological anthropology and biomechanical engineering have explored fractures in ribs; however, biological anthropology has focused more so on information that can be gleaned from medical records or postmortem specimens, and biomechanical experiments generally use ribs which have been separated from the rib cage and are tested individually.

Biomechanical experiments often apply force through a twisting outward motion called torsion. While many bones in the human body are more vulnerable to torsion, the ribs have a greater resistance to torsion than they do to an inward crushing force, specifically compression. Additionally, individual, or disarticulated, ribs have a freedom of movement not available to them when connected within a rib cage, which is formed by articulated ribs.

In this project, the researcher will address these knowledge gaps determining the different ways disarticulated ribs and articulated rib cages react to anterior pressure. The first hypothesis will be that disarticulated ribs will be more susceptible to fracturing with a secondary hypothesis of disarticulated rib fracturing occurring in an identifiably different pattern than those of articulated rib cages. Differences in fracture patterns between these two groups will call into question the validity of previous research when applied to real world contexts .

The second hypothesis concerning fracture timing will be that dry ribs - whether disarticulated or articulated - will differ in fracture morphology from fresh ribs. Knowing how to separate and identify postmortem damage and perimortem fractures would assist in forensic cases when determining the cause and manner of death. In forensic cases, understanding the cause of death can change how the case is treated legally including what charges are pressed and who might be suspected. In cases of genocide, understanding rib fractures would be helpful in indicating perimortem trauma which may be associated with torture. This project will increase our knowledge of how rib fracturing differs depending upon timing and articulation and, in doing so, advance forensic science.

ca/ncf