Forensic Medicine

1. Forensic Medicine Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang

2. Chapter 1General Consideration on Forensic Medicine

3. 1. Definition of Forensic Medicine Forensic Medicine, also called Legal Medicine, Medico-legal Medicine, or Medical Jurisprudence, is a branch of medicine, which deals with the interaction of medicine with the law by application of theories and techniques of medical science , biology and the other natural sciences.

4. 2. Interaction of forensic medicine with medicine Basic Natural Sciences Basic Medical Sciences Subjects as Medical Basis Medicine Clinical Medicine Applied Medicine Preventive Medicine Forensic Medicine Sports, Compensation Medicine

5. 3. Branches of forensic medicine (1) Forensic pathology It deals with the examination of the dead, to investigate the cause of death, manner of death, estimate the time course of death and age of wound, etc. Unnatural deaths, sudden unexpected deaths as well as their pathological examination and pathogenesis. Deaths involved in violence or suspected violence, deaths suspicious of medical malpractice. Deaths from industrial disasters. Forensic pathology may also be thought of as the ‘pathology of trauma’.

6. (2) Clinical forensic medicine It deals with the examination of living individuals. Its main tasks cover several aspects including : Evaluation of severity of injuries and illness resulted from wounds, Working ability, Investigation of physical abuse and sexual function, Examination of victims of sexual assaults, the accused of criminal abortion and pregnancy, Inspection on simulated or artificial disease or injuries and drunken status.

7. (3) Science of forensic material evidence Science of forensic material evidence, or forensic physical evidence mainly deals with : • The studies on bloodstains, body fluid stains such as saliva and semen; • The origin of hairs and tissue fragments; • The performance of personal identification and paternity tests by forensic serological techniques or DNA analysis.

8. To date, techniques in molecular biology such as DNA fingerprinting, examination of STR loci after PCR procedures have been widely used in the area. A sub-branch called forensic odontology may play an important role in estimation of age, sex, possible occupation by examination of denture and personal identity by tooth marks. Forensic anthropology is the sub-branch dealing with personal identification by study on bones and bone fragments, skin ridges and fingerprints as well as photo pictures.

9. (4) Forensic toxicology Forensic toxicology, the study of poisons largely devotes to mechanisms through which toxic substances function, the cause and manner of poisoning, symptoms and morphological findings as well as determination of lethal dose of poisons.

10. (5) Forensic chemistry or forensic toxicological analysis Forensic chemistry (forensic toxicological analysis) mainly deals with qualification and quantitation of toxic substances in the biological fluids, tissues or other samples for toxicological purpose.

11. (6) Forensic psychiatry Forensic psychiatry is one of the sub-branches of forensic medicine, which is responsible for analysis and examination of human behaviour, personality, responsibility and psychiatric problems and resolution of legal matters involving psychological disorders, which may offer a profile of the assailant to law enforcement officers.

12. 4. The roles that forensic medicine play • To provide scientific information for disclosing crime facts • To give scientific facts for resolving inter-personal disputes • To provide scientific evidence for justice in court or public heath service to tackle with medical litigation over malpractice

13. 5. Purposes for which medical students learn forensic medicine • As an expert witness • As a professional witness • Exposing a crime • Prevention of medical malpractice • Providing evidence for medical insurance

14. 6. The jobs forensic practitioners undertake • Crime scene investigation • Autopsy • Examination of the living individuals • Test of the collected material evidence

15. (1) Crime scene investigation • Crime scene is referred as to any place where the deceased or any physical or trace evidence connected with the crime are discovered. • More than one crime scene may be encountered. • Crime scene investigation is a consecutive detective action. • Places and objects involved in crime must be investigated and examined, the suspected searched and the deceased autopsied.

16. Upon arrival at the scene of death, request a summary of what is known about the incident, the protection of the scene, the time of arrival as well as condition of the weather. • Work out a practical and effective plan for investigation in the light of the scene and then begin to search. • Record observations at the scene, photograph the body and the scene. • Make a sketch of the scene when necessary. Any object that had to be moved at the scene should be definitely marked in place.

17. After photographs are taken, scene investigation may begin with the investigators gathering at the center of the scene and moving out in spoke-like directions. On arrival at the scene, the body should be examined to determine whether it is alive or dead. A comprehensive external examination of the deceased may be carried out only after the crime scene investigation is nearly complete. During the investigation attentions should be paid to the following aspects:

18. 1. Are the bloodstains, fingerprints or any physical evidence left by the criminal at the entrance, passageway or staircase of the crime scene, any physical evidence in the waste basket and garbage can? • 2. Whether the newspapers or documents in the crime scene are touched and read? What is the issue date? • 3. Are there any odors (alcoholic drink, cigarette smoke or gunfire smoke)? • 4. Is there any dinner meal left? Are there saucers, bottles or food residue? The fingerprints left on the saucers or bottles, the cigarette tips ashes, fired matches in the ashtray or on the ground should be cautioned. • 5. Whether closet, drawers of the furniture are turned over? Are there any fingerprints on the furniture?

19. 6. Is there any damage to the ceiling, wall and furniture at the crime scene? Is the damage connected with the assault? • 7. Are there fired shells, bullet entrances present on the ground, the walls, the ceiling in the homicidal cases that the firearm is involved? • 8. Where do the ligatures come from in the cases of hanging or ligature strangulation? • 9. Careful searching places where weapons may be hidden should be implemented. • 10.Are there posthumous paper and fingerprints on the paper left at the scene in the cases of suicide?

20. (2) Autopsy Medico-legal autopsy must be conducted under one of the following circumstances: • 1. Autopsies must be performed on the bodies to determine the causes of death in criminal cases and on the unidentified bodies to determine the cause and manner of death; • 2. On the decedents who suddenly and unexpectedly died when homicide or suicide is suspected; • 3. On the bodies that are involved in the legal matters due to industrial or agricultural poisonings or grave infectious diseases.

21. The purposes of the medico-legal autopsy are: • To establish the causes of death, which is focused on determining whether the death is violent or non-violent. • To interpret the mode or manner of death. • To estimate the time of death. • To conjecture the possible weapon inflicting wounds. • To conduct personal identification

22. (3) Examination of the living individuals The jobs involved in the examination of the living individuals include: • Inspection of wounds • Medico-legal expertise on working ability • Appreciation of disease • Investigation of sex-associated problems • Psychiatric evaluation • Paternity test • Investigation of simulation and self-mutilation

23. (4) Test of collected material evidence • Material evidence is any tangible article or trace left by the offender during perpetration, by which the criminal and his crime act may be judged to some extent. • Material evidence varies with cases and may be analyzed in the specialized laboratories. • In the medico-legal laboratory, any trace physical evidence such as bloodstain, semen stain, salivary stain, hairs, urine, feces, tooth or bone fragments can be examined. • When necessary, facial restoration or reconstruction may be used for personal identification.

24. In the toxicological laboratory, foods, drugs, poisons, drug bottle packing sheets, syringe, vomit, body fluid, visceral tissues can be analyzed. In the criminalistic laboratory, fingerprints, foot marks, tool impressions, cartridge, explosive residue, paint, detonation device, ink stains, paper sheet, stamp pad and questioned documents can be examined in comparison.

25. Chapter 2Death and Postmortem Phenomena

26. Section 1 Death 1. Definition of Death Death is always considered to be cessation of life. Traditionally, death has been defined as complete and persistent cessation of respiration and blood circulation. • Cardiac death • Respiratory death • Brain death

27. (1)Cardiac death, which is referred to as the death resulted from stoppage of heart beating before cessation of respiration. Cardiac death is often caused by such heart diseases as • coronary heart disease • cardiomyopathy • valvular disease • pericardial effusion • cardiac conducting system abnormalities • cardiac trauma, etc.

28. (2) Respiratory death, which is referred to as the death that is resulted from cessation of respiration prior to stoppage of heart beating. Respiratory death is mainly due to: • obstruction of airway such as hanging, strangulation by ligature, manual strangulation, drowning, and overlay, • pulmonary diseases such as pulmonary edema, pulmonary parenchyma, pulmonary emphysema, pneumonothorax, pulmonary infarction, • respiratory center paralysis, respiratory muscular paralysis due to muscular relaxant poisoning, • hypokalemia, etc.

29. (3) Brain death, which is referred to as the complete cessation of the total brain function, including activities in the cerebrum, cerebellum and brainstem, although heart beating may exist and/or spinal cord may function. i. Cause of brain death • Cardiac failure due to myocardial infarction, standstill, valve dysfunction • Head trauma • Cerebral apoplexy (stroke) • CNS infectious diseases • Intoxications • Other miscellaneous conditions

30. ii. Respirator brain Respirator brain was created to describe a condition of brain in that brain death has occurred in patient whose breathing is supported continuously with ventilator or respirator. Gross pathology of “respirator brain” • The brain appears dusky gray, and congested • The brain reveals generalized swelling with evidence of tonsillar herniation or the other herniations • The brain is soft, often mushy, or nearly liquid • The cerebellum and brainstem are often macerated and fragments of the cerebellar tonsils may have fallen into the spinal canal • The pituitary gland appears strawberry-like

31. iii. Criteria for certifying brain death (a) The patient should be in deep coma, show no response to even intensely painful stimuli. (b) There should be no spontaneous respiration for three minutes when taken off the ventilator. (c) There should be no reflexes; the pupils should be fixed, dilated, and unresponsive to light; no eye movement should be elicited by turning the head or by cold water irrigation of the ears; there should be no corneal reflexes; no blinking; no postural activity, pharyngeal reflexes, and no swallowing, yawning, vocalization; no deep tendon reflexes should be present.

32. (d) The EEG should be flat for at least 10 min of technically adequate recording; there should be no response to noise or pinching. (e) There should be no change in any of the above tests when repeated after 24 hr. (f) There should be no evidence of hypothermia, nor of CNS depressant drugs present in the blood. 2. Death Process • Agonal stage • Clinical death • Biological death

33. (1) Agonal stage It varies with causes of death, even lack of such a stage in some cases, or may last relatively longer period, about several hours, in the cases dying from chronic illnesses. Clinical manifestations • Malfunction of CNS and mental disturbance such as delirium and coma. • Failure of recognizing dependents or friends due to visual loss. • Feeble heart contraction without producing any palpable pulsation and hearable heart sound.

34. (2) Clinical death which is also called somatic death or individual death. Characteristics : • Cessation of circulation and spontaneous respiration, • No reflexes elicited. • This stage may last 5- 6 min in which cerebral cortex might survive without oxygen or from hypoxia in essence.

35. (3) Biological death Death occurs in cells and tissues in this stage. Thus, death in this stage is also called molecular death or total death. Characteristics • Complete cessation of cellular metabolisms and irreversible damage of the cells. • Early signs of death: cessation of circulation and respiration, dilated pupils, disappearance of any reflexes • Early postmortem changes: muscular flaccidity, the cooling of the body, and the rigidity of the body, etc.

36. 3. Apparent death (1) Definition Apparent death is defined as the state of minimum of life activity, which is characterized by appearing dead, even no any palpable pulsation and audible breathing as detected by simple, conventional clinical methods. (2) Causes leading to apparent death A: anemia, apoplexy, and asphyxia such as mechanical asphyxia ( hanging, suffocation or choking, throttling or manual strangulation and drowning or death from immersion, etc.)

37. E: electrical injuries. I: injuries, especially head injury. O: opium, i.e., poisoning of opium and the other sedative drugs such as CNS depressants. U: uremia. Other causes : brain concussion, hypothermia, low environmental temperature, sunstroke, malnutrition.

38. 4. Classification of death in forensic medicine (1) Violent death (a) Suicidal death or suicide, which is self-inflicted by violent manner. (b) Homicidal death or homicide, which is caused by others by violent ways. (c) Accidental death, which is induced by such accidents as natural, industrial or agricultural disasters. (2) Non-violent death which is also called natural death, is any death caused by diseases and abnormalities or aging, but it is very common that an individual dies from sickness.

39. Section 2 Postmortem Phenomenon Postmortem changes are referred to as a series of physical, chemical and morphological changes that occur in cadaver due to the influences of physical, chemical and biological factors inside and outside the body as cessation of metabolism and functional activity occur after somatic death. The appearances revealed in the cadaver as result of postmortem changes are termed postmortem phenomena. • The early postmortem phenomena • The late postmortem phenomena The early postmortem phenomena are referred to those occurring 24 hours after death, whereas the late ones beyond 24 hours after death.

40. 1. The early postmortem phenomena (1) Muscular flaccidity Muscular flaccidity is the condition where there is complete relaxation of the muscles developing at the time of death, which is also known as the primary muscular flaccidity. Contact flattening of the muscles occurs during muscular flaccidity. Alterations of the position after death may be indicated by the presence of the areas of contact flattening on parts of the body which no longer lie in contact with a solid surface.

41. (2) Algor mortis Algor mortis, also called cooling of the body is another important phenomenon that begins to occur at the time of death. • Three major ways by which the human body loses heat, i.e., by radiation, convection and vaporization. • Factors affecting the rate of cooling of a body i. The mean atmospheric temperature during period of cooling • The rate of cooling is rapid in a cold day. • The rate of cooling is rapid during the night . • Cooling of the body does not occur in the atmospheric temperature above 40℃.

42. A body cools more rapidly in the open air than in a small poorly ventilated room. • Cooling is more rapid in a humid temperature than in a dry atmosphere. ii.The presence or absence of clothing or othercoverings on the body after death • The cooling is relatively slow in clothed bodies. iii.The state of nutrition and development of the body • The cooling of a large body is relatively slower than the cooling of a small body. • The cooling is greatly retarded in obese as compared with the thin subjects.

43. iv. The causes of death affecting the rate of cooling of the body The rate of cooling of the body may be slower in the cadavers with the conditions such as infectious diseases of bacterial origin, epileptica status, and pontine hemorrhage. In cases of barbiturate intoxications, the rate of cooling of the body can be more rapid. By recording the temperature of a body and calculating the rate of cooling of the body at crime scene, we can estimate the time of death. If combined with the other early postmortem phenomena, estimation of time since death may tend to be more accurate.

44. (3) Livor mortis  i. Definition: After death, the blood gravitates to the dependent portions of the body. The dependent capillaries and veins become distended. This capillovenous distention is known as postmortem hypostasis. Livor mortis is the appeared color in the portions of the body due to capillovenous distention, which is also termed postmortem lividity. ii. Distribution of the postmortem lividity and hypostasis (a) External appearances of the lividity In the supine position, the lividity is distributed externally over the dorsal aspect of the trunk, the posterior aspects of the head and neck, extensor surfaces of the up limbs and the flexor surfaces of the lower limbs.

45. In the supine position, lividity is not observed over the back of the crown of the head, the backs of the shoulders, the buttocks and the backs of the heels because pressure prevents the filling of the veins and capillaries of the skin in these areas. A ventral distribution of lividity is seen externally in a prone position after death. In this case, the lividity is distributed externally over the forehead, the cheeks and chin, the upper parts of the chest and abdomen, and the extensor surfaces of the lower limbs. In the prone position, the lividity cannot be found in the area of the mouth and nose, the part of the chest because of contact pressure in these areas.

46. In the upright position, lividity is usually found in the dependent lower limbs, the external genitalia, the lower parts of the forearms, and the hands and the parts surrounding the waist above the waist-band. When the position of the body is uncertain, the distribution of the lividity is different, for instance, in death from immersion, the body usually floats face downwards, with the back of the chest at the highest level in the fluid, lividity may be most marked in the face, over the front of the trunk and in the limbs.

50. (b) Internal appearances of the hypostasis The site of distribution of hypostasis in the viscera depends upon the position of the body. In the supine position, hypostasis is seen in the posterior portions of the cerebrum and cerebellum, the dorsal portions of the lungs, the posterior wall of the stomach, the dorsal portions of the liver, the kidneys, and the lowermost coils of the intestine in the pelvic cavity.