DEATH:
Death is defined as an irreversible cessation of circulation, respiration and cerebral function. It should be considered as a process of degeneration of body rather than an event. It results in the extinction of the biological functions that define a living organism. Scientific community presumes death to terminate mind or consciousness. Humans and other animals die in due course because of ageing. Death can occur due to malnutrition, disease or accident resulting in physical injury. Intentional human commotion which can lead to death includes war, suicide and homicide.
Universal symbol for death Fig 1a Photograph of Dead individual
“In Australian law, death is generally defined as either irreversible cessation of circulation of blood in the body of the person or irreversible cessation of all function of the brain of the person.”
AUTOPSY: (Postmortem examination, Necropsy (Particularly to animals), Autopsia cadaverum or obduction).
INTRODUCTION:
Autopsy is a medical procedure which includes thorough examination of a dead body with a aim of determining cause and manner of death. It helps to evaluate any disease or injury that might have caused death.
Postmortem examination is necessary in unnatural death to know the cause behind death which inturn will be helpful for for legal and administrative purpose. For example, Forensic autopsy is performed to determine cause of death in criminal matter, clinical or academic autopsy is done to find the medical cause of death and is used in uncertain death or for research purposed. Autopsies can be grouped into,
‘ Cases where external examination suffices.
‘ Dissection of body is done for performing internal organ examination.
An autopsy is performed by a physician trained in pathology. Autopsy means “see for you”. It is a special surgical operation, conducted by trained medical personal on a dead body. Autopsies further help to know the truth about the person health during life, and how the person really died. The main aim of an autopsy is to determine the cause of death, health status of the person before he/she died and to know about the medical diagnosis given before death.
Fig 2 Photograph of Autopsy
Autopsy is conducted on dead individual of unnatural cause. It has to be conducted in association with the legal authority (Medical Examiner or Coroner or Procurator Fiscal) and do not require the consent of relatives of the deceased.
Example in the examination of murder victims, especially when medical examiners are looking for signs of death or the murder method, such as bullet wounds and exit points, signs of strangulation, or traces of poison. Some relegions in the world usually discourage autopsies because of their religion restriction. Essential requirement of performing autopsy has to guided to those families and also mention the requirement in legal and also administrative purpose.
History:
An autopsy can be mentioned as the examination of a deceased human body with a detailed exam of the person’s remains. This procedure dates back to the Roman era when few human dissections were performed. Autopsies were utilized, however, to determine the cause of death in criminal cases. The term “autopsy” is derived from the Ancient Greek word AUTOPSIA which mean “to see for oneself”. Ancient Egyptians around 3,000BC were first civilizations to practice the removal of internal organs and their examination.
Autopsies were opposed in many ancient societies believing that the outward disfigurement of dead body prevented them from entering after life. Egyptians removed the organs through tiny slits in the body. In 44 BC, Julius Caesar was the subject of an official autopsy after his murder by rival senators, and the physician’s report noted that the second stab wound Caesar received was the fatal one. By around 150 BC, ancient Roman legal practice had established clear parameters for autopsies.
The dissection of human remains for medical reasons continued to be practiced irregularly after the Romans, for instance by the Arab physicians Avenzoar and Ibn al-Nafis, but the modern autopsy process derives from the anatomists of the Renaissance. Giovanni Morgagni (1682’1771), celebrated as the father of anatomical pathology, wrote the first exhaustive work on pathology, De Sedibus et Causis Morborum per Anatomen Indagatis (The Seats and Causes of Diseases Investigated by Anatomy, 1769).
Medical researchers Rudolf Virchow and Carl von Rokitansky built on the new beginning inheritance to derive the two distinct autopsy techniques that still bear their names. Their demonstration of pathological conditions in dead bodies and symptoms and illnesses in the living opened the way for a different way of thinking about disease and its treatment.
Most cultures have historically had a strong aversion to mutilating the dead human body or to dissecting it simply to learn normal anatomy. Yet the world’s ancient and classical civilizations had equally strong prohibitions against murder. In India, China, and around the Mediterranean, the ruling orders developed legal systems that defined murder and established procedures in which witnesses testified that external marks on the body, or other visible signs, distinguished suicides, accidental deaths, and natural deaths from murder. In medieval Europe, twelfth-century legal scholars first extended the common practice of viewing the external signs on a body to identify probable cause of death, to examining the internal marks of violence or disease. The question of which wound corresponded to the fatal blow, for instance, could be crucial for picking out the murderer from those involved in a group assault. Poison, too, was thought to leave visible marks in the stomach that an expert might identify. Opening the body to serve justice thus outweighed distaste for such procedures. Early autopsies were likely to be quite short and minimally defacing because the inspection was limited to the area of the thorax or abdomen under particular scrutiny. The history of the autopsy in Western Europe and Great Britain is thus closely tied to the evolution of legal systems and court procedures. In English (and later American) law, the development of the duties of the coroner, a lay person, kept the decision to order a medical inspection, whether external or internal, out of the hands of medical experts until the nineteenth century.
Forensic autopsy procedures antedated the introduction of lawful human dissection into medical schools, which first emerged in medieval universities in the early fourteenth century. It is important to distinguish autopsies, where legal officials sought the cause of death, from anatomical dissections, where anatomists and, much later, medical students, learned normal anatomy. The former had a legal purpose the latter only seemed to satisfy human curiosity. When dissection was introduced into universities and surgical guild throughout the late medieval and early modern periods, secular rulers only permitted dissections of executed criminals. The continued association of dissection with mutilation and post-mortem punishment helped to maintain cultural aversion to autopsies.
Medical autopsies, where the body is opened simply to determine the cause of a natural death, emerged in Europe only after the rise of the study of normal anatomy in the sixteenth century. Even then, physicians and elite surgeons performed such inspections only sporadically until the eighteenth century, primarily because the dominant theory of the humors which explained both health and disease in terms of individualized balances of the body’s main fluids, accounted for the visible marks of pathology on organs as being the effects of underlying disease imbalances.
TYPES OF AUTOPSIES:
Two common types of autopsies are,
- Forensic/corner’s autopsy; performed to identify the casue and manner of death. It can be even performed to identify the decendent.
Example: In cases of violent, suspicious or sudden deaths, deaths without medical assistance or during surgical procedures.
- Clinical/Academic autopsy; are performed for research purposes.
Example: to determine, clarify, or confirm medical diagnoses that remained unknown or unclear prior to the patient’s death.
FORENSIC AUTOPSY;
A forensic autopsy is used to determine the cause of death. Death can be placed in one of five manners,
‘ Accident.
‘ Homicide.
‘ Suicide.
‘ Natural.
‘ Undetermined ( Undetermined death category include deaths in absentia, such as deaths at sea and missing persons declared dead in a court of law).
After the thorough examination of all evidence medical examiner can give out manner of the death. in addition to it is necessary to explain the possible mechanism of death depending on the evidence available.
DEATH BY NATURAL CAUSES:
Death by natural causes is term used by medical examiner describing death when the cause of death was a naturally occurring disease process, or was not apparent given medical history or circumstances. (It may also be described as death by “multiple organ failure”). Thus, deaths caused by active human intervention (as opposed to the failure of medical intervention to prevent death) are excluded from this definition, and are described as unnatural deaths. “Old age” is not a scientifically recognized cause of death there is always a more proximal cause, such as cancer, heart disease, or liver failure (though the precise cause may be unknown in a particular case, and it could be one of a number of aging-associated diseases).
Deaths due to any disease process are deaths by natural causes. The “unnatural” causes are usually given as accident (sometimes termed “death by misadventure”), suicide and homicide. In some settings, other categories may be added. For example, a jail system may track the deaths of inmates due to acute intoxication separately.
DEATH BY ACCIDENT:
An accident is a specific, identifiable, unexpected, unusual and unintended external action which occurs in a particular time and place, without apparent or deliberate cause but with marked effects. It implies a generally negative probabilistic outcome which could have avoided/prevented if recognized and acted upon prior to its occurrence. Preferred words are more descriptive of the event itself, rather than of its unintended nature (e.g., collision, drowning, fall, etc.)
Fig 3 Photograph Collapse of Building
Accidents of particularly common types (automobiles, fire, etc.) are investigated mainly to prevent the main cause behind such incident and to take necessary action so that such incident should not be repeated in future. It can be called as root cause analysis, but does not generally apply to accidents that cannot be deterministically predicted. A root cause of an uncommon and purely random accident may never be identified, and thus in future similar accidents remain “accidental.”
Accident is constrained to an immediate incident, the occurrence of which results in an unplanned outcome. In common use, however, ‘accident’ may include the entire interacting circumstantial framework (chance, pre-existing, or uncontrolled dynamically developing conditions, commonplace actions, random time and place, participants etc.) leading up to, including and resulting from, the accident’s immediate occurrence.
Accident includes Physical and Non-Physical. Physical examples include unintended collisions or falls, being injured by touching something sharp, hot or electrical, or ingesting poison. Non-physical examples are unintentionally revealing a secret or otherwise saying something incorrectly, forgetting an appointment, etc.
Fig 4 Photograph Fire in building
DEATH BY HOMICIDE:
Homicide (Latin homicidium, homo human being + caedere to cut, kill)
It refers to the act of a human murdering another human being.
example, would be murder. Homicide is not always an illegal act, so although “homicide” is often used as a synonym for “murder,” this is not formally correct.
Fig 5 Photograph murder of an individual
Homicides sometime may not be considered as crime like in
‘ Self defense to criminal charges. Here it can be stated that person is entitled to commit homicide to protect his or her own life from a deadly attack.
‘ Capital punishment, in which the state determines that a person should die.
‘ Action during war are usually not subject to criminal prosecution.
‘ Members of law enforcement entities are also allowed to commit justified homicides within certain parameters which, when met, do not usually result in prosecution.
DEATH BY SUICIDE:
Suicide (Latin suicidium, from suicaedere, to kill oneself) is the intentional killing of one’s self. The most common cause is underlying psychiatric disorders which include depression, schizophrenia, alcoholism and drug abuse, financial difficulties or other undesirable situations play a significant role in the developing world.
Fig 6 Photograph death due to Hanging
Views on suicide have been influenced by cultural views on existential themes such as religion, honor and the meaning of life. The Abrahamic religions consider suicide an offense towards God due to religious belief in the sanctity of life. In the West it was often regarded as a serious crime. Japanese views on honor and religion led to seppuku (also called hara-kiri), one of the most painful methods of suicide, to be respected as a means to atone for mistakes or failure, or as a form of protest during the samurai era. In the 20th century, suicide in the form of self-immolation has been used as a form of protest, and in the form of kamikaze and suicide bombing as a military or terrorist tactic. Sati is a Hindu funeral practice in which the widow would immolate herself on her husband’s funeral pyre, either willingly, or under pressure from the family and in-laws.
Medically assisted suicide (euthanasia or the right to die) is currently a controversial ethical issue involving people who are terminally ill, in extreme pain, and/or have minimal quality of life through injury or illness. Self-sacrifice for others is not usually considered suicide, as the goal is not to kill oneself but to save another.
CLINICAL AUTOPSY;
Clinical autopsies are necessary for two main reasons
‘ To gain insight into the factors leading to pathology and death.
‘ To ensure the standard of care at hospitals.
Autopsies can yield insight into how patient deaths can be prevented in the future. In some countries clinical autopsies can only be carried out with the consent of the family of the deceased person. They are necessary in clinical medicine because they identify the medical errors and help medical personnel for continous improvement.
Fig 7 Photograph TISSUE SHOWING PATHOLOGY
FORENSIC PATHOLOGY:
It is a branch of pathology concerned with determining the cause of death by examination of a cadaver. Here autopsy are performed by the pathologist at request during the investigation of criminal and civil cases. Forensic pathologists are also frequently asked to confirm the identity of a cadaver. Physical examination of the body both external and internal examination is necessary for pathologist in order to assign the cause or causes of death.
Fig 8 Photograph Cadaver dissection table
EXTERNAL EXAMINATION:
Person who will be responsible for handling, cleaning, and moving the bodies are called as DIENER the German word for servant. Once the body is received it has to be photographed. Examiner has to note about the clothes, their position on the body before they are removed. Evidence such as residue, flakes of paint or other material is collected from the external surfaces of the body. Ultraviolet light may also be used to search body surfaces for any evidence not easily visible to the naked eye. Samples of Hair, Nails and the like are taken, and the body may also be radiographically imaged if necessary.
Fig 9 Photograph samples showing dress used by individual when last met
Fig 9a Photograph samples showing Hair sample
Once the external evidence is collected body has to be undressed and careful examination is necessary for injuries /wound present of body surface. If any injury/wound noted complete description is necessary The body is then cleaned, weighed and measured in preparation for the internal examination.
The body is transported to autopsy room and placed on a table. Body regarding ethnicity, sex, age, hair color and length, eye color and other distinguishing features (birthmarks, old scar tissue, moles etc) has to be noted. A standard examination form is normally used to record this information. Countries like in France, Germany and Canada, an autopsy may comprise an external examination only. They consider that medical records, history of deceased and circumstance of death will indicate caus and manner behind death, hence internal examination is not necessary. This concept is sometimes termed a “view and grant”.
Fig 10 external examination suggests death due to blood loss (hemorrhage and Shock.
INTERNAL EXAMINATION;
Before examining the internal organs it is necessary to prepare the body for proper visualization. It can be achieved by placing a plastic or rubber brick ( “body block”) under the back of the body, allowing neck to fall back, pushing chest upward and allowing the arms stretching to make it easier to incise and cut open. This gives the prosector, a pathologist or assistant, maximum exposure of the trunk. Following the exposure internal organs has to be incised and removed inspected carefully for any evidence of trauma or other indications of the cause of death.
Internal examination can be achieved by incising the body. Different approaches available includes,
‘ Large and deep Y-shaped incision: here incision should be given at the top of each shoulder, running down the front of chest meeting at lower point of sternum. It is often used in forensic autopsies where maximum exposure of structure is necessary for detailed examination. Example in cases of suspected strangulation.
‘ T-shaped incision: incision is made from the tips of both shoulder, in a horizontal line across the region of the collar bones to meet at the sternum (breastbone) in the middle. This initial cut is used more often to produce a more aesthetic finish to the body when it is re-constituted as stitching marks will not be as apparent as with a Y-shaped incision
‘ A single vertical cut: it is made from the middle of the neck (in the region of the ‘adam’s apple’ on a male body)
In all of the above cases the cut then extends all the way down to the pubic bone.
Fig 11 Photograph incision given.
During incision bleeding from cut surface may be minimal or absent due to pull of gravity. It can also be directly related to the complete lack of cardiac functionality. However, in certain cases there is undependable evidence to prove that bleeding can be quite profuse, especially in cases of drowning.
An electric saw dubbed a “Stryker saw” is most often used to open the chest cavity. Even shears are used to cut chest cavity to prevent large amount of dust formed due to cut of bone by saw. Simple scalpel blade can also be utilized to cut the bone. Ribs on the lateral sides of the chest cavity and the sternum to be lifted as one chest plate this is done so that the heart and lungs can be seen in situ. In particular the pericardial sac should not be damaged or disturbed from opening. Soft tissue that is attached to posterior side of the chest plate has to be removed by using a scalpel. Lungs and the heart have to be exposed. The chest plate is placed aside which can be replaced at the end of the autopsy. Once the body internal organs are exposed they are removed either in en masse technique of letulle where all organs are removed as one large mass if not by en bloc method of Ghon.
One method is described here,
1. The pericardial sac is opened to view the heart. Blood for chemical analysis may be removed from the inferior vena cava or the pulmonary veins. Before removing the heart, the pulmonary artery is opened in order to search for a blood clot. The heart can then be removed by cutting the inferior vena cava, the pulmonary veins, the aorta and pulmonary artery, and the superior vena cava. This method leaves the aortic arch intact, which will make things easier for the embalmer. The left lung is then easily accessible and can be removed by cutting the bronchus, artery, and vein at the hilum. The right lung can then be similarly removed. The abdominal organs can be removed one by one after first examining their relationships and vessels.
2. Some pathologists, however, prefer to remove the organs all in one “block”. Then a series of cuts, along the vertebral column, are made so that the organs can be detached and pulled out in one piece for further inspection and sampling. During autopsies of infants, this method is used almost all of the time. The various organs are examined, weighed and tissue samples in the form of slices are taken. Even major blood vessels are cut open and inspected. Next the stomach and intestinal contents are examined and weighed. This could be useful to find the cause and time of death, due to the natural passage of food through the bowel during digestion. The more area empty, the longer the deceased had gone without a meal before death.
Fig 12 a, b ,c d Photograph Different organ removed during PM
RECONSTITUTION OF BODY;
It is an important step which has to be done with an utmost care during autopsy. Reconstitution of the body has to be done so that it can be viewed, if desired, by relatives of the deceased following the procedure. After the examination, the body has an open and empty chest cavity with chest flaps open on both sides, the top of the skull is missing, and the skull flaps are pulled over the face and neck. It is unusual to examine the face, arms, hands or legs internally. All organs and tissue must be returned to the body unless consent is given by the family to retain any tissue for further investigation. Normally the internal body cavity is lined with cotton wool or an appropriate material. The organs are then placed into a plastic bag to prevent leakage and returned to the body cavity. The chest flaps are then closed and sutured back together and the skull cap is placed back in place and flaps are sutured.
Fig 13 Photograph Skull opening
INDICATIONS FOR AUTOPSY:
While a request for autopsy should be made the following criteria indicate situations in which autopsies are particularly warranted,
1. To help explain unknown or anticipated medical or surgical complications.
2. When the cause of death or a major disease is not known with reasonable clinical certainty.
3. To provide reassurance to the family and/or the public regarding the death.
4. When there is unexpected or unexplained death that is apparently natural and not subject to the medical examiner’s jurisdiction.
5. In a natural death possibly subject to, but waived by, the medical examiner, such as person dead on arrival at hospital.
6. In a death in which the patient sustained or apparently sustained an injury while hospitalized.
7. When an unexpected or unexplained death occurs during or following a diagnostic procedure and/or therapy.
8. To disclose a known or suspected illness that may have a bearing on surviving family members or recipients of transplanted organs (e.g., genetic disorders or unsuspected cancer).
9. In death resulting from high-risk infection or contagious disease (for public health concerns).
10. In death known or suspected to have resulted from an environmental or occupational hazard (for compensation or public health aspects).
11. To confirm or further define a prenatally diagnosed condition after termination of pregnancy.
12. In pregnancy loss (miscarriage, spontaneous abortion, or intrauterine fetal demise) or stillbirth.
13. In neonatal (death within 28 days of life) or pediatric death.
14. To correlate anatomic findings with imaging or other diagnostic studies.
15. For educational purposes or in an unusual case.
16. When the patient participated in a clinical trial or protocol.
17. To obtain tissue for research purposes.
While autopsies should be requested in all hospital deaths, certain cases require medical examiner review; by law the coroner can order a post mortem examination in some circumstances, such as accidental death. The coroner’s office will contact you directly about this if it is necessary. Deaths under the jurisdiction of the medical examiner include,
1. Homicide.
2. Suicide.
3. Accidental death (even long after the initial injury).
4. Sudden death in apparent good health.
5. Death unattended by a physician.
6. Suspicious circumstances surrounding the death.
7. Sudden Infant death.
ORAL AUTOPSY:
Similar to general autopsy oral autopsy is a postmortem assessment or examination of an oral cavity. Immediately after registration, all bodies and other evidence found may be brought to the center selected for direct examination. The medical expert performs the general autopsy, often attended by a police officer. The dental expert performs the oral autopsy. His examination should be conducted along particular lines on account of the number of decisive details that he may be able to unveil. Thus, the oral autopsy may require more time than the general autopsy. The first thing is to find and prepare for examination all dental evidence actually present.
If, in a given body, the facial tissues and bones have not been mutilated, dental characteristics may still exist. However, it may prove impossible to force the jaws apart for inspection. This may be the consequence of pronounced rigor mortis or of excessive combustion. It may therefore become necessary to remove a rectangular area of the cheeks, including the lips, in order to expose the facial surfaces of teeth still in position. It may also prove necessary to remove the tongue and the tissues below the mandibular base, in order to be able to move the mandible downward and gain access to the occlusal and oral surfaces of the teeth. When the oral autopsy has been completed, removed parts may be restored to position and fastened with transparent tape. In cases of this type, the teeth themselves are generally clean and can be directly examined and described.
Fig 14 Photograph tongue placed out
If, on the other hand, facial structures and bones are fractured or smashed, it is first necessary to find and to rearrange those parts of the jaws still present. This must be done to see whether there are empty sockets, indicating that the corresponding teeth have been lost. Such teeth must be looked for. They may be lying at some distance or even have been lodged deep in the throat or under the scalp. Single teeth may also have been found lying loose in the accident area and will, consequently, have to be looked for in some separate bag. All teeth that may belong to the body under examination must be tried in their respective sockets to see whether they fit. In this way, remaining parts of the teeth and jaws may be restored to their original positions.
Fig 14 a Photograph Suggestive of antemortem blow on face
ESTIMATING TIME OF DEATH:
Time of death seems to be a simple and straightforward term that obviously means the exact time that the victim drew his last breath. Unfortunately, it’s not quite that simple.
There are actually three different times of death:
‘ The physiologic time of death, when the victim’s vital functions actually ceased.
‘ The legal time of death, the time recorded on the death certificate.
‘ The estimated time of death, the time the medical examiner estimates that death occurred.
It is important to note that the estimated time of death can vary greatly from the legal time of death and the physiologic time of death.
The determination of time of death is of crucial importance for forensic investigators, especially when they are gathering evidence that can support or deny the stated actions of suspects in a crime. The time elapsed from the moment of death until a corpse is discovered is also known as the postmortem interval, or PMI. Both the time of death and the postmortem interval cannot be determined with 100% accuracy, particularly when a body is found in advanced state of decomposition or is recovered from fire, water or ice. Therefore, time of death and PMI are given as estimates, and can vary from hours to days or from months to years, depending on each particular case.
An accurate estimation of time of death can lead to discovering the identity of the assailant. In criminal cases, it can eliminate some suspects while focusing attention on others. The time of death is not confined to criminal investigations; it also comes into play in civil situations. Insurance payments may depend upon whether the insured individual was alive at the time of policy went into effect or if he died before policy expired. Likewise, property inheritance can hinge on when the deceased actually died. For determining the time of death medical examiner has to use several techniques and observations to make his estimate. As a general rule, the sooner after death the body is examined, the more accurate this estimate will be.
Evidence for estimating time of death includes physical evidence present in the corpse (postmortem changes, presence of insects, etc.), environmental evidence such as location where the body was found (indoors, outdoors, buried, burned, in water, etc.), and other evidence found at the crime scene (a stopped wrist watch due to a blow or impact, an answering machine record, phone calls received or made around the time of the assault, etc.), and finally, the historical evidence (habits and daily routine of the victim, relationships, existence of enemies, etc). The knowledge of the internal sequential changes a dead body undergoes in relation to the variations on the rate of their occurrence due to ambient temperature, humidity, and the presence of insects or other predators are all considered when estimating the time of death.
The classical method of estimating time of death is the rate method, which measures postmortem (after death) stages and the types of transformation a body undergoes such as cooling rates (algor mortis), stiffening (rigor mortis), initiation and duration, postmortem lividity (discoloration stains), degree of putrefaction, adipocere (body fat saponification), and maceration (tissue softening due to the presence of liquid).
Algor mortis, or the process of body cooling, is a useful parameter for PMI estimation during the first 24 hours after death, as the internal body temperature drops at known rates. However, these rates are valid only in cool or temperate climates because hot summer seasons or tropical temperatures slow down the loss of heat and, in some regions, can even raise postmortem temperatures due to rapid putrefaction through bacterial activity inside the digestive tract. Other variables interfering with postmortem cooling rates include the size of the body, amount of subcutaneous (under the skin) adipose (fatty) tissue, existence of clothing and coverings, air currents and humidity, and the medium where the body remained after death (such as inside a closed car, under water, on ice or snow, or inside a metallic container).
Rigor mortis, or postmortem stiffening and contraction of all muscles, usually occurs three or more hours after death and can last for approximately 36’48 hours in temperate climates and about 9’12 hours in tropical temperatures. If a murderer moves a body before rigor mortis (RM), the new position will be “frozen” during RM, not the original one that would have characterized the pattern of the body falling at the crime scene. Therefore, the position a body shows during rigor mortis cannot be assumed as the position in which the victim was at the moment of death. The rigor mortis phase is not the best time for the pathologist to determine the cause of death, because several changes take place in the internal muscles, such as the heart and the ocular muscles, which can be misleading. For example, rigor mortis dilates the myocardial (heart) muscles, giving it the appearance of cardiac hypertrophy (enlarged heart). Contraction of the iris muscles also dilates the pupils during rigor mortis.
Fig 15 Photograph showing Rigor mortis
The factors that interfere with the onset and duration of rigor mortis are temperature, existing antemortem pathologies, age, body muscular mass, and the degree of muscular activity immediately before death. Higher temperatures shorten the time till the onset of rigor mortis and its time of duration. A strong fight or lengthy physical effort before death causes an earlier onset and shorter duration of rigor mortis. Children and older adults have also earlier rigor mortis than younger adults. Generalized infections or long, debilitating diseases also produce earlier onsets and shorter periods of rigor mortis, whereas extensive antemortem bleeding or death due to asphyxia delays rigor mortis onset.
Livor mortis, or postmortem lividity, is characterized by the reddish/purple discoloration of the skin, sometimes with a pink border, in consequence of the lack of the arterial pressure that counteracts the gravitational force. Therefore, when blood circulation ceases, the blood is gradually deposited in the lower internal vessels and in the lower parts of the body, with the signs of livor mortis usually appearing within the first hour after death. However, in many cases it can appear 2’3 hours after death, and is usually fixed after about 12 hours. Livor mortis rates of appearance are delayed by severe anemia and starvation, but can be present before death in individuals slowly dying from circulatory insufficiency.
Fig 15a Photograph showing Livormortis
Postmortem decomposition or putrefaction consists of the destruction of soft tissues, usually starting internally through the action of microorganisms present in the stomach and bowel and in the nasal pharyngeal pathways. Open wounds also provide access to bacteria from the environment to the body. Obesity accelerates the putrefaction process, as well as infectious conditions, congestive cardiac failure, or when edema (swelling with fluid) is present. Conversely, extensive external bleeding during death or severe dehydration delays the putrefaction onset. As mentioned before, temperatures may accelerate or delay putrefaction onset and rates. Gases derived from the putrefaction process are used to estimate time of death, known as the Brouardel method. According to this approach, in the first postmortem 24 hours, abdominal gases are not flammable; between the second and the fourth day they are flammable, from the fifth day on, they are not flammable again. Putrefaction stains start to form on the abdominal skin around 24’36 hours after death in temperate climates and in 12’18 hours in tropical regions. These stains are green and gradually appear all over the body between the third and the fifth day after death. As the blood undergoes putrefaction, crystal blades are formed in fragmented or clustered patterns, crisscrossed and colorless. These crystals start forming after the third day and can remain in the blood up to 35 days. Determining time of death by observing blood crystals is known as the Westernhoffer-Rocha-Valverde method, and was first applied in forensic medicine by the Brazilian forensic pathologists Martinho da Rocha and BelmiroValverde.
The first postmortem transformative event, known as autolysis, consists of spontaneous self destruction of tissues by enzymes present in the cells without bacterial interference. One of the byproducts of autolysis is the building up of potassium ions concentrations known as vitreous humor potassium (VHP), and occurs during the first 20 postmortem hours. The quantitative analysis of the concentration rates of VHP is one of the adjuvant methods for PMI estimation when combined with other measurements.
Postmortem tissue survival rates constitute another PMI estimation method. Different types of tissues lose their vital properties in different moments of the postmortem interval. For instance sperm cells show motility for about 36 hours after death. Muscles react to electrical or mechanical stimuli for a postmortem interval of six hours, and pupils can be dilated with atropine until four hours after death. Leukocytes, the white blood cells, die at the following PMI rates: 8% during the first 5 hours, 58% within 30 hours, and 95% within 70 hours.
Corpses exposed to outdoor environments attract insects with different behavioral habits and life cycles. Another modern technique utilized in time of death estimation involves forensic entomology. Forensic entomology utilizes insects on or surrounding the body, as well as their eggs and larvae, to estimate the amount of time a body has been dead and left in a certain environment. Entomology is useful as a forensic tool because the life cycles of insects are both well known and predictable. In addition, the succession of colonization of a corpse by insects occurs in temporally specific waves of different species.
In addition, bloodstains found at the scene of a crime can yield clues or confound police. Bloodstains could have been recently deposited, or possibly been there for a period of time from events unrelated to the crime under investigation. New and innovative techniques are now being used to establish time of death and age of bloodstains. These new techniques help forensic scientists and criminal investigators reconstruct more representative crime scenes and more precisely determine time of death.
Decomposition is a mixed process, ranging from cell autolysis due to internal chemical breakdown to tissue autolysis due to liberated digestive fluid. Dr.Gururaj, Dr.Sivapathasundaram showed the initiation of decomposition at cellular level and determined the approximate time of death by histological examination of gingiva in postmortem cases.
Fig 16 Photograph Histology of cell autolysis
In recent days since teeth are more resilient to environmental factors measuring the rate of degradation of nucleic acids (DNA and RNA ) in these tissues has been used as a method for estimating the PMI for longer time intervals, from days and weeks, months and years.
POSTMORTEM PINK TEETH:
Pink teeth phenomenon is a common postmortem finding noted by forensic dentists. It has to be differentiated from the antemortem pinkish discoloration of teeth especially along the cervical portion of the teeth and along the root portion which is commonly associated with decomposition in a moist environment. Exact notification of the pink teeth phenomenon is not known within the literature first explanation regarding pink teeth in victims of hanging or drowning was made by Bell in 1829. Postmortem pink teeth can be made out in people who has dead due to drowning, hanging, knifing, barbiturate poisoning, carbon monoxide and CO2 poisoning, also unknown cause. Usually pink appearance is more pronounced at the region of cemento-enamel junction than other parts of the teeth at the same time this appearance of pink teeth is more intense among anterior teeth than the posterior teeth.
Beely and Harvey conducted biochemical investigation into the nature of the post-mortem occurrence of pink teeth including iso-electric focusing after homogenisation, pH measurements and carbon monoxide detection and concluded that presence of the pink pigment as haemoglobin and/or its derivatives. Kirkham et al in 1977 concludes that Pinkness occurs due to seepage of fluid containing hemoglobin or its degradation products derived from decomposition or liquefaction of the tooth pulp into the dentinal tubules. However exact cause of the pink discoloration remains unexplained few authors suggests that it is due to great physical trauma and moist environment play role in its appearance.
Fig 17 Photograph POSTMORTEM PINK TEETH
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