The main part of my internship at the Forensic Anthropology Center at Texas State (FACTS), other than processing and labeling remains, has been to document rates of decomposition using two different scoring techniques. The data collection is going to be used to create a paper or poster showing the trends and rates of decomposition in Texas, which will provide more clarity to postmortem interval calculations in Texas.
The Forensic Anthropology Research Facility (FARF) is a location owned by Texas State where donations are either buried or placed on the surface for research purposes. . From the day of placement until skeletonization is reached, data collection and photographs are conducted daily to mark any changes in decomposition. Once skeletonization is reached the remains are disarticulated and are brought to the Osteology Research and Processing Laboratory (ORPL). The remains are processed at this point in order to be labeled and added to the growing research collection at the Grady Early Forensic Anthropology Research Laboratory (GEFARL).
The goal of my project was to collect enough data in order to provide a substantial amount of evidence showing that rates of decomposition are not as black and white as was previously thought. I collected data on certain donations at FARF twice per week between January and April. At the time of this paper there are seventy-nine bodies at FARF.
In order to record the level of decomposition for each body, two scoring systems were used. The first system of scoring I used during data collection was from an article that provides a way to conduct total body scoring (Megyesi, Nawrocki, & Haskell 2005). Megyesi et al.’s (05) method of scoring uses a quantitative approach to assess the changes in decomposition. The method of finding a total body score is to rate a body by dividing it into three different zones: “the head and neck, including the cervical vertebrae; the trunk, including the thorax, pectoral girdle, abdomen, and pelvis; and the limbs, including the hands and feet” (Megyesi, Nawrocki, & Haskell 2005).
Each of these areas of the body are given a score corresponding to subcategories under the categories of fresh to skeletonization. The maximum scores range from ten to thirteen, depending on the area of the body being scored. Once each area is scored, they are added together to obtain the total body score for the individual. The total body scores can range from three to thirty-five, depending on the stage of decomposition of the individual. This score, along with accumulated degree days (ACD), will help to narrow down the post-mortem interval of an individual.
The second scoring system I employed was based on a study conducted in Arizona, which provides a different scoring system for arid and hot environments of the Southwestern United States (Galloway, Birkby, Jones, Henry, & Parks 1989). The data collection method derived from this article is simpler than the Megyesi et al. (05) method. In my opinion, the Galloway et al. (89) method of scoring is much less accurate in Texas. I came to this conclusion due to the lack of correlation between the options provided from the scoring chart and the actual data I collected.
For this process of collecting data the date and time are noted along with whether the donation is in the sun or shade. The individual as a whole is then given a number of one to five corresponding to the categories of fresh, early decomposition, advanced decomposition, skeletonization, and advanced skeletonization. The problem which occurs with this method is a lack of description under each category and the fact that in this arid region of Texas advanced skeletonization almost never takes place. There are decomposition factors which are descriptions of a category, but do not necessarily always fall under that category in this region of the United States. This goes to show the rate of decomposition is incredibly variable, even within one region. From this study and the data gathered, I have found that the most effective way of rating decomposition would be to create a different method for use in this arid region of Texas rather than using a method for use in the entire Southwestern region of the United States.
My findings after using these two methods of scoring over the course of my internship varied mostly due to weather patterns. Until the last few weeks of data collection the weather was either cold or moderate, which contributed to very slow decomposition. During the few weeks of warm to hot weather, the donations decomposed much more rapidly. I created a chart showing how many days it took each donation to reach the main categories of fresh, early decomposition, advanced decomposition, and skeletonization. The chart I used was derived from an article which uses the (Megyesi, Nawrocki, & Haskell 2005) method of scoring in order to further solidify the research on decomposition in the Southwestern region of the United States (Parks 2011).
The difference between desiccation and mummification is one of the most interesting pieces of information I acquired during my time spent at FARF. The first insight I gained into this difference was from a question I asked a graduate student referring to the different texture on the chest versus the feet of a particular donation. This led me to further research the processes of desiccation and mummification in order to gain a better understanding of the difference and why they differ. According to Segal (2013), there are many factors which can accelerate mummification. These factors include, but are not limited to: moisture, food, oils, plant residue, and animal fat.
Mummification occurs most often in arid environments and is the result of trapped moisture. Once this process takes place, it is very unlikely that further decomposition leading to skeletonization will occur. From my experiences at FARF, mummification usually occurs in the hands and feet and does not result in bone exposure. Desiccation, on the other hand, mostly occurs over the chest and stomach regions and does result in bone exposure. The process of desiccation is mostly due to large amounts of heat, which goes along with the fact that there has not been much desiccation at FARF during the cold months of my internship. Mummification and Desiccation seem to generally be caused by the same factors, but there is a clear visual difference after field experience.
I thoroughly enjoyed my internship with FACTS. I gained a wealth of knowledge. This experience has provided me with a much better understanding of osteology, taphonomy, and how forensic studies are used in the field. One of my favorite parts of this experience was being able to read many articles on rates of decomposition, while physically seeing those changes take place. Even with quantitative research, no two donations decompose in the same manner, which has made every day interesting and exciting. The most beneficial knowledge base I have gained from my internship has been a better understanding of osteology and how it is practically used. In classes, students are given mostly whole bones and have to side and identify them, but in the field one has to identify many bone fragments. For example, there were many times during disarticulation when a sesamoid from the foot would be found and we would have to work as a team to figure out what exactly it is and what side it came from in order to correctly complete inventory lists all of the remains. Identifying bones while disarticulating and processing has taught me much more about osteology than simply studying for a test in a classroom. This entire experience has been priceless and I look forward to taking the knowledge I have gained with me upon graduating and hope to learn even more as I establish a career in forensic sciences.
- Galloway, Alison, et al. “Decay Rates of Human Remains in an Arid Environment.” Journal of Forensic Sciences (1989): 607-616.
- Megyesi, Mary S, Stephen P Nawrocki and Neal H Haskell. “Using Accumulated Degree-Days to Estimate the Postmortem Interval from Decomposed Human Remains.” Journal of Forensic Sciences (2005).
- Parks, Connie L. “A Study of the Human Decomposition Sequence in Central Texas.” Journal of Forensic Sciences, (2011).
- Shirley, Natalie R, Rebecca J Wilson and Lee Meadows Jantz. “Cadaver Use at the University of Tennessee’s Anthropological Research Facility.” Clinical Anatomy (2011): 372-380.
- Siegel, Jay. Encyclopedia of Forensic Sciences, Second Edition. Academic Press, 2013.