Photometric measurement of pressure-induced blanching of livor mortis as an aid to estimating time of death

Abstract

A newly developed digital system employs photometric measurement of pressure-induced blanching of livor mortis to estimate time of death. The conventional method of applying pressure with thumb or forceps relies largely on subjective interpretation. Our system improves on this method by photometric quantification of color changes produced by defined magnitudes of pressure. We tested the new system by applying increasing levels of pressure to lividity in 50 cadavers with known time of death. Characteristics courses for pressure-induced changes were found for the brightness component of livor mortis, revealing distinct differences between the respective postmortem intervals. The surface areas under these curves were then calculated and distributed into 10-hour postmortem time categories. Variance analysis of these surface values revealed clear differences between the time categories, especially in the medians. Distinct differences between the various postmortem time categories were also evident for the chroma component of livor mortis. The new system offers a further method--in addition to body temperature, rigor mortis, and the electrical responsiveness of skeletal muscles--for estimating time of death, especially after long postmortem intervals.

Gross and Histologic Postmortem Changes of the Skin

“…Certain external physical characteristics used to estimate the time of death 2 include the degree of livor mortis, 3 rigor mortis, body temperature changes, 4,5 insect activity, 6 -9 decomposition chemistry of the remains, 10,11 and degree of decomposition, such as green discoloration, bloating, and marbling. 1 All of these can be influenced by factors such as the premorbid condition of the body, movement of the body, cause of death, body mass, temperature and humidity of the environment, and animal and insect activity.…”

Developing Synaesthesia

“…Color coordinates in the CIE L * a * b * systems, used in analyses of the results, were converted from the CIE xyY coordinates of presented colors; all were measured using Topcon BM-7 luminance colorimeter. We adopted the CIE L * a * b * system because it was designed in such a way that mathematical differences in all color ranges correspond to perceived color differences (Kaatsch et al, 1993). We further converted the color coordinates in the CIE L * a * b * system to coordinates in the CIE L * C * h system in order to obtain hue, saturation, and luminance values.…”

Re-oxygenation of haemoglobin in livores after post-mortem exposure to a cold environment

“…Altogether, there are only a few studies dealing specifically with the colour of livor mortis [2,12,16,25], although several attempts have been made to provide an objective way to determine the colour of livores in particular with regard to the chronological order of occurrence, intensity, shifting and displaceability [13,14,26,29,30].…”