Estimation of Time since Death in Australian Conditions

By Jarvis Hayman

Estimation of Time since Death in Australian Conditions collates data about decomposed bodies found in the eastern states of Australia from the years 2000 to 2010. The book takes into account that over 70% of decomposed bodies were found within 14 days. From standard autopsy reports, a quantitative method of assessing the degree of decomposition in four specific body organs and the total appearance of the body was collated into a total body score (tbs). The mathematical models on how to estimate time since death in the eastern states of Australia are covered in this valuable resource.

• Explores national statistical data concerning decomposed human bodies
• Presents Total Body Score (TBS) from standardized autopsy reports
• Includes research to prove the efficacy of a TBS from actual autopsies and actively decomposing bodies at a forensic research facility
• Presents a compilation of mathematical models to estimate the time since death in human bodies found decomposed indoors in the eastern states and the Northern Territory of Australia

• Language: English
• Publisher: Academic Press
• Release date: Feb 12, 2021
• ISBN: 9780128245613

Jarvis Hayman

Jarvis Hayman is a retired surgeon who studied archaeology, completing a Master’s degree at the Australian National University in Canberra with a thesis on the archaeology of the Scottish Highland Clearances. He then combined his medical and archaeological knowledge to complete a PhD on the estimation of the time since death in decomposed human bodies in Australian conditions. His research areas of interest are: historical archaeology and forensic archaeology/anthropology. He is a Visiting Fellow at the Australian National University and the co-author of Human Body Decomposition.

Book preview

concluded.

Chapter 1

A review of research concerning the estimation of time since death in decomposed bodies in the early stages of decomposition

Abstract

Research into the estimation of time since death from the early 19th century until the present day is outlined. It begins with estimation from supravital reactions and continues with estimation from temperature measurement as the body cools to ambient temperature. Temperature-based estimation has concentrated on the search for a mathematical formula to improve the precision of estimation, culminating in the formulation of Henssge’s nomogram. Then follows a description of research into biochemical methods: the estimation of vitreous potassium being the best biochemical method to date. A brief description of other promising but more complex biochemical methods is given.

Keywords

Muscle excitability; livor mortis; rigor mortis; algor mortis; Henssge’s nomogram; vitreous potassium

Research in the modern era began with a seminal paper by Dr John Davy in Ceylon (Sri Lanka) (Davy, 1839). Sporadic research was carried out in the latter part of the 19th century followed by a period of time during the war years of the early and mid-20th century when no research was carried out. In the late 1950s and in the 1960s, research efforts increased and were given an impetus in the 1980s with the establishment, by Dr W M Bass of a facility to carry out research with human cadavers at the Forensic Anthropology Centre of the University of Tennessee in Knoxville, United States, popularly known as ‘The Body Farm’ (Bass and Jefferson, 2004). Most research has been concentrated in finding a method to estimate the time since death (TSD) in the early stages when the body is cooling to ambient temperature. Once putrefaction has become established and especially when the body has become skeletonised, estimation of the TSD becomes increasingly difficult and less accurate.

Until the latter part of the 20th century the only quantitative research carried out were attempts to more accurately estimate the TSD during the cooling phase of the body. Research in the stage of putrefaction was mainly qualitative, with attempts to clearly define the stages of decomposition in various environments and case histories predominating. In recent years, it has been increasingly recognised that quantitative methods of defining the process of putrefaction are required if the estimation of the death interval is to become more accurate. The literature will be reviewed in this and the next chapter, in a temporal sequence concerning both time and the stages of the decomposition process as they progress, beginning with the early post-mortem phases of livor mortis, rigor mortis and algor mortis, followed by biochemical methods of estimating the post-mortem interval (PMI) in body tissues and fluids. Research during the stage of putrefaction will be reviewed before considering research during the stage of skeletonisation. Finally, current concepts and the future direction of research will be discussed.

1.1 Immediate post-mortem or supravital reactions

At death and following cessation of the circulation, some body tissue remains reactive to mechanical and electrical excitability of skeletal muscle and the reaction of the pupil to the application of catecholamines. Mechanical muscle excitability may occur up to 13 hours post-mortem and ocular reaction to catecholamines up to 46 hours (Henssge et al., 1988). In 1780 Luigi Galvani, experimenting on dissected frogs, discovered that electrical stimulation of the spinal cord caused muscle contraction in the legs (Goetz, 1987). Further research was carried out in the 19th century, but there was a lapse until the 1960s when most studies were carried out in Germany and reported in the German language. Madea and Henssge (1990) reviewed the use of electrical stimulation of muscle tissue and its efficacy in estimating the PMI, the theory of its use being that the force of contraction declined with the passage of time and that this could be measured. They concluded that the results of various studies were not comparable because the position of the electrodes and the parameters of excitation and grade of muscular contraction were not standardised. However, by combining the method of stimulation of the orbicularis oculi muscle with the use of their nomogram method after temperature measurement, the accuracy was increased (Henssge, 1988). The method is only of use for about 12 hours after death and requires practice and standardisation by the person using it.

1.1.1 Livor mortis

Livor mortis is the process where blood pools in dependent tissues following cessation of the circulation. It is first noticed as a purple discolouration beginning about 2 hours after death and for a period of time it is not fixed, that is an area of lividity subjected to pressure will become white, as the deoxygenated blood is pressed back into the capillaries. The area of lividity will also move to another dependent region if the body is moved during this period. After about 4–6 hours, it becomes fixed, that is the area does not blanch on pressure and does not shift with body position because capillaries in the dermis are occluded by the surrounding fat as it solidifies (Clark et al., 1997). Other observers have noted a different time sequence; lividity becoming apparent from 20 minutes to 2 hours after death, reaching maximum intensity in 6–9 hours and becoming fixed from 3 to 5 days (Vanezis and Trujillo, 1996). The appearance has been divided into categories: (1) beginning, (2) confluence, (3) maximum intensity, (4) slight pressure displacement, (5) complete shifting and (6) incomplete shifting (Swift, 2006). However, these categories are subjective, are dependent on individual qualitative assessment and are of little use in the quantitative estimation of the PMI.

A preliminary study to determine the degree of lividity by colorimetry and equating it with the PMI was carried out on 26 cadavers (Vanezis, 1991). In a larger study, 93 cadavers in whom the time of death was known to within 3 hours were subjected to colorimetric study (Vanezis and Trujillo, 1996). The bodies kept at 4°C were placed in the prone position and the degree of luminosity on their backs measured at four hourly intervals up to 72 hours. A strong correlation was found between the degree of luminosity and the PMI, lividity becoming darker with increasing PMI in an exponential fashion. After 72 hours lividity became fixed. There were only a small number of cases in this series and the authors concluded that factors such as body size, cause of death, body position, environmental temperature and skin colour could affect the luminosity.

A computer-aided system for measuring pressure-induced blanching of livor mortis as a means of estimating the TSD was described by Kaatsch et al. (1993). In a later study of 50 cadavers, photometric measurement was made of areas of post-mortem lividity after using standardised pressure on the areas (Kaatsch et al., 1994). Some bodies were stored at 12°C–15°C, but some had been stored at variable temperatures before measurements began at 10 hours after death and continued until 40 hours after death. This study resulted in over 20,000 values of brightness and colour difference values which were analysed with a computer programme. The baseline brightness of an area of lividity at various time intervals was measured, as well as the difference in brightness of the same area after standardised pressure was applied. It was confirmed that brightness decreased with the increase in PMI in an exponential fashion up to 40 hours after death. Kaatsch et al. (1994) noted that wide variations in their data could be attributed to factors such as skin colour, ante-mortem physical condition, cause of death and ante- and post-mortem environmental factors such as temperature and storage conditions prior to