Estimation of Time Since Death from Rigor Mortis - An Autopsy Study in Tertiary Care Hospital of Malwa Region of Punjab state of India

Abstract

Background: Postmortem interval estimation is an important tool in forensic medicine. Estimating time since death is extremely important in cases where there is doubt about the period of death. After death, many changes occur in a regular sequence and can be used to arrive at an approximate time since death. When a post-mortem is conducted, doctor conducting the post-mortem examination has to give his opinion about post-mortem interval i.e. the probable time that elapsed between death and post-mortem examination even in cases of decomposed dead bodies. While giving this opinion, we always think we should have some other dependable methods to be more accurate in answering this question. Algor mortis, Rigor mortis, and Livor mortis have been the basis for ascertaining the post-mortem interval collectively. Among them, Rigor Mortis is an important indicator of post-mortem interval. Although it is a dependable tool for estimating post-mortem interval, it is influenced by many endogenous and exogenous factors like nature of death, nature of the body, temperature, humidity etc. Time of death is almost always asked by investigating authorities to connect the crime with criminals. Determining the death time has always been a topic of keen interest amongst forensic pathologists from its inception to date. Many workers in forensic medicine have tried to investigate to determine the time of death based on post mortem findings. To date, it is still an important and fascinating criterion to ascertain the time since death. With this study, we aimed to demonstrate the intricacies of Rigor Mortis with fluctuating temperature and humidity of the local region. We planned to estimate and compare the post-mortem interval based on Rigor Mortis in different body muscles. Materials and Methods: This study was conducted in the Department of Forensic Medicine and Toxicology at G.G.S. Medical College, Faridkot after taking clearance from the institutional ethics committee. Thirty medico-legal autopsy cases were included in the study where the exact time of death was known and included only hospital deaths. The relatives of the deceased were explained the purpose and nature of the study and provided with the patient information sheet and informed consent was taken. The details of the cases were noted from the hospital bed head ticket, relative interview and the police inquest papers. The exact temperature and humidity were noted at the start of autopsy using a digital hygrometer. Results: A total of 30 cases were observed out of which males outnumbered the females by approximately 3:1. Maximum cases consisted of Roadside Accidents (43.3%) followed by poisoning, assault and hanging, in that order. The average temperatures during the study months varied from a maximum of 41.3°C (June) to a minimum of 33.7°C (July). The average humidity varied from a maximum of 62.6% (July) to a minimum of 29.3% (May). The average temperatures during the study months varied from a maximum of 41.3°C (June) and a minimum of 33.7°C (July). The average humidity during the study months varied from a maximum of 62.6 % (July) and a minimum of 29.3% (May). Fully established Rigor Mortis was observed at a minimum of 10 hours and a maximum of 29 hours in May and June.

New Methods for Establishing Time of Death when Dealing with Natural Mummification from Bog Environments

“…Natural mummification is a process in which an organism's remains are preserved. This requires spontaneous conditions that allow for quick dehydration, including hot climates, dehydration in freezing climates, or preservation by an anaerobic and acidic environment (Joshi 2021). The specific methods for forming natural mummies can vary depending on the environmental conditions.…”

“…During this process, Adenosine 5′-triphosphate (ATP) is converted to Adenosine diphosphate (ADP), and lactic acid is produced, which lowers the cellular pH-leading to chemical bridges between actin and myosin. This causes the muscles to lock up, resulting in the characteristic stiffness of rigor mortis (Joshi 2021). Livor mortis, also known as post-mortem lividity or hypostasis, is the physical process by which blood accumulates in the blood vessels of the lowest parts of the body due to gravity (Vass 2001).…”

“…Livor mortis, also known as post-mortem lividity or hypostasis, is the physical process by which blood accumulates in the blood vessels of the lowest parts of the body due to gravity (Vass 2001). This causes discoloration of many body parts, ranging from bright red to dark purplish (Joshi 2021). When looking to find the PMI of natural mummies or any discovered body, the decomposition of the body and other indicators, such as insect activity and weather conditions, are considered when analysts do their estimation.…”