- Medicolegal Investigation of Death
- Sudden Death
- The Autopsy
- Post Mortem Interval
- Identification of the Dead
- Wounds I
- Wounds II
- Thermal Injury/Fire Deaths
- Immersion and Drowning
- Asphyxial Related Deaths
- References and Further Reading
Medicolegal Death Investigation has been described as the aspect of forensic science which deals with the dead body. The Death Investigator plays one role in the investigative team- evidence gathering and interpretation of the decedent.
Medicolegal Death Investigation and the investigation of crime are inextricably linked. However, this is a relatively recent marriage.
The history of death investigation or forensic medicine also belongs with that of public health.
Dr. Angela Dijanic
Death is one of the true certainties of life. Experience tells us that the majority of people will die quietly and peacefully from entirely natural causes – some within their own home, others surrounded by loved ones within a hospital setting. Although these individual deaths are, of course, tragic events for the relatives and friends of the decedent, they do not usually require the attention of the medicolegal investigator. Nor do they raise profound ethical, scientific or religious dilemmas.
The concept of death has never existed in a vacuum. It is, rather, culturally conditioned and contingent on the nature of beliefs, expectations and, indeed, fears of society. The ancient Egyptians, for example, saw death as a transition in the journey of the person to a life in the next world. The need to preserve the body and provide sufficient food and other useful items for the journey and the next life is reflected by their elaborate funeral rituals. Within the Judaic-Christian tradition, too, death is viewed as a gateway for the redeemed to enter a new existence: the moment of death being the departure of the Soul from the mortal body. From a more pragmatic perspective, death has been defined simply as the point at which the heart stopped beating and breathing ceased. In some cases, the fact of death is obvious: decapitation or putrefaction (“Ashes to Ashes, Dust to Dust”) are sure signs of certain death. However, even in these cases, individual cells may still be alive. Fibroblasts, for example, can continue to grow in culture for several days after death, dependent on the condition of the body. It has been suggested that hair and finger nails continue to grow after a person has died, but this is generally accepted as myth and any appearance of growth likely stems from dehydration post mortem, causing shrinkage of skin exposing more hair or nail than was seen prior to death. The death of the entity (somatic death) has to be distinguished from the death of each and every individual component (cellular death). A nuclear blast is an event in which somatic and cellular death occur simultaneously.
As medical science and, equally important, technology improved, there was an increasing awareness that “death” was not a simple definable event but rather a complex process. As techniques were developed to maintain ventilation, circulation, nutrition and the elimination of the waste products of metabolism artificially, a person whose brain had died could be kept “alive”. In 1959, the concept of “brain death” was proposed (Mollaret P & Goulon M, 1959). Although the debate as to when a patient might be declared “dead” emerges about the same time as transplantation technology was being developed, it is erroneous to assume that “brain death” was motivated solely by the desires of transplant surgeons to acquire adequately perfused and fresh organs. However, there can be no doubt that organ transplantation and the possibility of beating heart cadavers presented huge challenges to philosophers, ethicists and, indeed, doctors.
Regardless of whether the manner of death is known or remains undetermined, legal requirements mandate the completion of a death certificate listing the cause of death. Death certification serves not only the deceased's relatives, but the larger community as a whole. Who is charged with determining the information that appears on a death certificate and how does this impact sociological trends?
The death certificate is an official document and in most jurisdictions follows the guidelines issued by the World Health Organisation (http://www.who.int). The section of the death certificate which is used to state the cause of death is divided into two parts. The primary cause of death (Part I) should be the condition which led directly to death whilst Part II should include any “contributory” causes of death. As a general rule, Part I states what the person died of whereas Part II states what the person died with.
The certificate is subdivided so that conditions which underlie the final cause of death are listed. These conditions form a chain which leads from the initiating “event” to the medical reason why the person died. In a forensic case, the initiating event is often a physical occurrence such as a motor vehicle collision, gunshot, stab wound or fall from a height. Note that the phrase “motor vehicle collision” is preferable to “road traffic accident” because it is neutral as to the manner of death.
The terminology used on death certificates differs according to the jurisdiction.
The majority of people die of natural causes. However, such deaths can be sudden and unexpected and are, therefore, of potential forensic interest. Indeed, the majority of deaths referred to most forensic units are sudden, natural deaths.
In the western world the vast majority of sudden unexpected deaths in adults are due to cardiovascular disease. Within countries there is often a significant variation in mortality rate by region and population.
An autopsy is a postmortem examination involving the dissection of the body. The word “autopsy” is derived from the Greek “auto” and “opsis” (literally “looking at the self”). Necropsy means the same although this term tends not to be used except in the USA.
The function of the autopsy depends on the context. In the forensic setting, a medicolegal autopsy is carried out primarily to establish the cause of death. This information might be required in a court of law and the autopsy report must also provide a plain English explanation of the cause of death and should be retained as a permanent (signed) copy of the medical evidence. The forensic autopsy is not a research, education or training tool and it has little value in auditing clinical diagnosis, intervention or treatment.
Before discussing the autopsy in detail, it is important to draw attention to two principles underlying the medicolegal investigation of death.
The "Rules of Death Investigation"
1. Respect for the Human Body
Although the pathologist and technicians have to carry out a series of invasive procedures on the deceased’s body, they do so ever mindful of the fact that the body was a human person: someone’s father, daughter, husband or sister… This person also had beliefs - these should be respected as far as possible.
2. Health and Safety
The dead body is a source of potential hazards. Health and safety concerns demand, therefore that a risk assessment is carried out and standard operating practices adopted (and observed) to minimize the risk to all staff in the mortuary.
One of the most vital pieces of evidence in any case involving a dead body can be the answer to what appears to be a straight-forward question - “when did the person die?” The gentleman detective / doctor so beloved by the “romantic crime” genre is likely to look at the deceased’s wristwatch and announce the time of death to be the time as shown on the now fractured and distorted face. The most reliable answer to the question is, however, likely to be obtained from an unbiased eyewitness to the event.
Attempts to determine how long a dead body has been lying since death have gone on since recorded history began. Numerous myths and half-truths have accumulated around this topic and detective fiction is replete with them even now. It is only quite recently, since the end of the C19th, that proper scientific methods have been applied to the problem.
Numerous changes take place in dead bodies. Some are biochemical and electrical, others induced by micro-organisms. The rate of most of them depends upon the temperature of the environment. A hot environment tends to speed up postmortem changes and a cold one slows them down. Thus it is not surprising that attention has focused on postmortem cooling.
In practice, in the absence of a reliable eye-witness,the single most important factor in estimating the post mortem interval is likely to be the experience of the forensic pathologist!
Is Any Body Anybody?
There are four different situations we need to consider:
1. Single Known Individual
2. Single Unknown Individual
3. Multiple Known Individuals
4. Mutiple Unknown Individuals
A wound can broadly be defined as an injury (or damage) to any part of the body by the application of trauma. The term "injury" has a wider definition. An injury encompasses damage to any part of the body or its function, whether occurring as a result of trauma or as a result of natural disease, such as death of the myocardium (heart muscle) after a myocardial infarction (heart attack).
There are four basic types of external injury or wounds:
Bruises or contusions
Incised wounds (including stab wounds)
In this module we look at cuts to the skin - the type of injury which can be caused by a variety of weapons including knives, axes, baseball bats, scissors, and fence posts - to name just a few.
Heat injury may arise from externally applied heat, or much more rarely, following a defect in body temperature control. Living mammalian tissue can survive only within a narrow range of temperatures, typically about 20°C to 44°C and, at the extremes, only for short periods.
The extent of damage produced by externally applied heat is related to:
the applied temperature
the ability of the body surface to conduct excess heat away
the time during which heat is applied
Just because a body is recovered from water, it should not be assumed that death was caused by drowning, nor indeed that the person was alive when he or she entered the water. Corpses recovered from water present many problems in interpretation, especially when there is delay in recovering the victim.
Bodies retrieved from water may have died as a result of:
* Natural disease before entering the water
* Natural disease while in the water
* Injury before entering the water
* Injury before being thrown into the water
* Injury while in the water
* The effects of immersion other than drowning
Drowning represents one of the three leading causes of unnatural death in the USA. It is estimated that the annual death rate for drowning is 2.5 per 100,000 of the population. The vast majority of drownings are accidental and male. Estimates vary, but it is thought that between 10% to 33% of drownings are suicidal with an approximately equal sex ratio. The relationship between alcohol and accidental drowning is well documented - the intoxicating effects of alcohol render the victim more likely to enter the water (voluntarily or involuntarily) and less able to recover.
Homicidal drownings are rare and the victims are usually children or disabled or elderly persons. The rate of drowning in populations around the world varies widely according to their access to water, the climate and the national swimming culture
What do we mean by "asphyxia"? It is a word which is commonly encountered in forensic circles. Etymologically the word means the absence of pulse although the term is used nowadays to denote a lack of oxygen.
The body requires oxygen to survive. The brain is especially vulnerable to a shortage of oxygen (hypoxia). If the brain is completely starved of oxygen (anoxia), consciousness is lost within about ten seconds. Death supervenes in approximately four to five minutes at normal temperatures.
Can you recall an example of prolonged survival in anoxic conditions?
At first reading, the phrase "lack of oxygen" might appear obvious. In fact, however, there are many entirely different circumstances which are relevant. In a forensic context, these "asphyxial mechanisms" include:
1-Absence of Oxygen in the Air
2-Inability to Inspire Oxygen
++Mechanical obstruction (external)
++Mechanical obstruction (internal)
++Failure of the muscles of respiration
3-Inability to utilize properly the available oxygen
In recent years, suicide has attracted the attention of investigators from a wide variety of backgrounds. Philosophers, theologians and ethicists have debated with psychiatrists, primary care providers and sociologists. Forensic investigators contribute to these debates because, by their professional effort and activity, much is known about the characteristics of people who take their own lives and, more generally, about the epidemiology of suicide.
The suicide of an individual is likely to affect many people - not just the deceased but family, friends and colleagues. Although the effect on this wider cohort is not the subject of forensic investigation, it is an important factor in the provision of adequate and appropriate health care and support services.
Suicide can also be considered to be a proxy indicator of the overall health and well-being of a society and it is important, therefore, that all apparent suicides are thoroughly and comprehensively investigated.
World Health Organization. www.who.int
Scottish Legislation www.scotcourts.gov.uk
Florida Legislation www.flsenate.gov/statutes
National Institutes of Health www.nih.gov
National Center for Health Statistics www.cdc.gov/nchs/
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