1. Biological Sciences Pathology Chapter 7 ©2010 Elsevier, Inc.

2. Pathologist is a medical doctor who studies and diagnoses disease in humans Forensic pathologist also studies trauma that leads to the death of an individual – Autopsy involves standardized dissection of a corpse to determine cause and manner of death INTRODUCTION ©2010 Elsevier, Inc.

3. Cause of death is divided into the primary and secondary causes of death – Primary or immediate cause of death is a three-link causal chain that explains the cessation of life starting with the most recent condition Most recent condition (is due to, or a consequence of) Next oldest condition (is due to, or a consequence of) Oldest (original, initiating) condition – Secondary cause of death includes conditions that are not related to the primary cause of death but contribute substantially to the individual’s demise – Medicolegal autopsy is performed pursuant to a medical investigation of death for legal purposes CAUSE AND MANNER OF DEATH ©2010 Elsevier, Inc.

4. Manner of death is the way in which the causes of death came to be – Homicide, suicide, accidental and natural – Purpose of autopsy is to establish cause and manner of death, identify deceased, establish time of death, or collect evidence surrounding death CAUSE AND MANNER OF DEATH ©2010 Elsevier, Inc.

5. The Coroner System – The position of coroner has evolved to encompass the investigation of unusual, untimely, or suspicious deaths – First coroner and medical examiners in U.S. were in Maryland colony – Position of coroner today can be appointed or elected, typically no formal education or medical training is required – A medical examiner is typically a physician who has gone through four years of university, four years of medical school, four years of basic pathology training and an additional one to two years of forensic pathology training Medical examiner is an appointed position CORONERS AND MEDICAL EXAMINERS ©2010 Elsevier, Inc.

6. Black states do not have coroners Map of Coroner/ME Systems ©2010 Elsevier, Inc.

7. THE POSTMORTEMEXAMINATION (AUTOPSY) External Examination – The Visual Examination Begins with description of deceased’s clothing, photographs of body and detailed examination of the entire body Trauma is noted on a form that includes notes, sketches, or recorded measurements ©2010 Elsevier, Inc.

8. Defense wounds are caused by a victim trying to defend himself or herself against an attacker VISUAL EXAMINATION  Stippling of gunpowder around a gunshot wound ©2010 Elsevier, Inc.

9. – Traumatic deaths may be classified as mechanical, chemical, thermal, or electrical – Mechanical Trauma Mechanical trauma occurs when the force applied to a tissue exceeds the mechanical or tensile strength of that tissue – Sharp force refers to injuries caused by sharp implements » Sharp objects produce incised wounds, or deep wounds CLASSIFICATION OF TRAUMA ©2010 Elsevier, Inc.

10. Blunt force refers to injuries caused by dull or non-sharpened objects – Blunt objects produce lacerations, or tears in the tissue Sharp trauma commonly causes death from a loss of blood or exsanguinations Blunt trauma commonly causes death from brain contusion or accumulation of blood in the tissues outside the normal blood vessels – Extreme contusion, or hematoma, is a blood tumor MECHANICAL TRAUMA ©2010 Elsevier, Inc.

11. Asphyxia is trauma in which the body is deprived of oxygen – Caused by suffocation, strangulation, or chemical asphyxiation MECHANICAL TRAUMA ©2010 Elsevier, Inc.

12. Projectile discharged from a firearm produces a special type of blunt force trauma GUNSHOT WOUNDS ©2010 Elsevier, Inc.

13. Chemical Trauma – Interactions of chemicals with the human body Thermal Trauma – Hypothermia is too much exposure to cold – Hyperthermia is too much exposure to excessive heat – Sick, elderly, or very young most often succumb to hypo- or hyper-thermia – Thermal burns are localized Persons who die in a fire do so generally because of asphyxia, or lack of oxygen, and inhalation of combustion products True thermal deaths occur due to massive tissue damage and/or swelling of the airway CLASSIFICATION OF TRAUMA ©2010 Elsevier, Inc.

14. Electrical Trauma – Electricity can cause death by a number of means Ventricular fibrillation is a random quivering of the heart that does not pump the blood through the body properly – Heart is pushed into tetany, a sustained contraction that is broken only when the circuit is broken CLASSIFICATION OF TRAUMA ©2010 Elsevier, Inc.

15. – Care is taken to preserve any trace evidence that may be later submitted to a forensic science laboratory – Age, sex, ancestry, height, weight, state of nourishment and any birth-related abnormalities are noted during exam – Body is examined for death-related phenomena that may provide information to the investigation Classification of Trauma ©2010 Elsevier, Inc.

16. Rigor mortis is the stiffening of the body after death due to the membranes of muscle cells becoming more permeable to calcium ions – Begins two to six hours after death, remains for two to three days 24 – 48 hours. – Muscles begin to relax when decomposition begins – Rate depends on activity before death and ambient temperature THE POSTMORTEM EXAMINATION ©2010 Elsevier, Inc.

17. – Livor mortis, or post mortem lividity, is the settling of blood due to gravity after the heart no longer circulates it through the body Results in purplish discoloration of the skin Sets in an hour after death and peaks in three or four hours Can indicate if a body has been moved THE POSTMORTEM EXAMINATION ©2010 Elsevier, Inc.

18. – Eye examinations also provide clues to pathologist Petechiae are pinpoint hemorrhages found around the eyes, the lining of the mouth and throat, as well as other areas – Also called Tardieu spots THE POSTMORTEM EXAMINATION ©2010 Elsevier, Inc.

19. – Swabs (vaginal, oral and rectal) are taken for submission to forensic or toxicological laboratory One set is taken for smears, whereby the collected fluid on each swab is wiped across a separate clean glass microscope slide – Examined for spermatozoa Second and third sets of swabs are for serological examinations – Known head and pubic hairs are collected during autopsy OTHER EVIDENCE COLLECTED ©2010 Elsevier, Inc.

20. – Ligatures, or victim’s bindings, are extensively photographed, sketched and collected – Full set of fingerprints is taken to be referenced against any databases – For badly decomposed remains, the jaw may be used for forensic dental examination and identification OTHER EVIDENCE COLLECTED ©2010 Elsevier, Inc.

21. – After external examination, internal organs are removed Stomach contents are examined thoroughly – Each organ is sectioned and viewed internally and externally Samples for microscopic analysis of the cellular structure, or histology, and for toxicology screening are taken INTERNAL EXAMINATION AND DISSECTION ©2010 Elsevier, Inc.

22. – Based on principle of sequential changes that occur following death called the postmortem clock Body temperature, livor, rigor, and decomposition – Decrease in body temperature is called algor mortis Chemical changes in body fluids or tissues Physiological changes with progression rates Survival after injuries DETERMINING TIME SINCE DEATH (POSTMORTEM INTERVAL) ©2010 Elsevier, Inc.

23. – The rate at which algor mortis occurs is not precise – Eyes are indicator of postmortem changes – Stomach contents may be used to determine PMI because the stomach empties at a known rate – Decomposition of the body begins almost immediately Autolysis is the disintegration of the body by enzymes released by dying cells Putrefaction is the disintegration of the body by the action of bacteria and microorganisms Four main steps of decomposition are fresh, bloated, decay, and dry – Dependant upon environmental factors DETERMINING TIME SINCE DEATH (POSTMORTEM INTERVAL) ©2010 Elsevier, Inc.

24. Histology – Examination for evidence of cellular pathologies resulting from disease, trauma, or preexisting conditions Tissue samples taken with a microtome, a machine that makes very thin, very precise slices Toxicology – Toxicology screens are broad-based screen tests that help to determine the absence or presence of drugs and their metabolites in human fluids and tissues LABORATORY ANALYSIS ©2010 Elsevier, Inc.

25. Autopsy Report – No standard reporting form exists, though all reports should include: Police report Medical investigator report Witness reports Medical history of the decedent LABORATORY ANALYSIS ©2010 Elsevier, Inc.

26. Exhumations – Exhumation is the digging up or removing of a deceased individual from a mausoleum Embalming may obliterate or obscure details that might otherwise be easily examined – Embalming is a process of chemically treating the dead human body to reduce the presence and growth of microorganisms, to retard organic decomposition and to restore an acceptable physical appearance Consultations – Forensic anthropologists, entomologists and odontologists may play a role in a death investigation LABORATORY ANALYSIS ©2010 Elsevier, Inc.

27. Medical examiners study disease and trauma that lead to the death of an individual Determine cause and manner of death CHAPTER SUMMARY ©2010 Elsevier, Inc.