Forensic Pathology

1. Forensic Pathology

2. Students Will Be Able To: • Discuss the definition of death. • Distinguish between four manners of death: natural, accidental, suicidal, and homicidal. • Distinguish between cause, manner, and mechanisms of death.

3. Death • Is the cessation of end of life • Irreversible cessation of circulation of blood • Irreversible cessation of all brain activity

4. Death • First stage of death is stoppage • Heart stops beating • Cells die because of no oxygen • Known as autolysis • Cells breakdown resulting in cell membrane dissolving and cell contents spilling out • Nerves, muscles, organs, and brain stop working

6. Forensic Pathologist • AKA medical examiner • Is a medical doctor • Works for the county or state

7. Job Duties • A medical examiner has 5 job duties • Identify the decedent • Determine the manner of death • Determine cause of death • Determine the mechanism of death • Determine time of death • Manner, cause, mechanism, and time of death determined during autopsy

8. Identification of the Decedent • To facilitate identification of a corpse, the following procedures are standard: • Physical Description • Scars and Marks • Fingerprints • Photographs • Age Determination—use of teeth for rough estimate • Dental Features • Radiological Evidence • Blood factors • Medical Indications • Other means

9. Manner of Death • Is the way that a person dies • There are five manners of death • Natural • Accidental • Homicidal • Suicidal • Undetermined • Autopsy findings are critical in determining the intent or mode of death

10. Natural Death • Death by natural cause is a term used by coroners to describe the death of someone by occurring disease process, or is not apparent given medical history or circumstances • The majority of natural death is caused by old age • Other causes of natural death are heart disease, stroke, genetic disorders, etc.

11. Accidental Death • Accidental death is a death that is often caused by mistake or in a freak occurrence • These deaths are not planned yet can be explained by surrounding circumstances

12. Homicide • The term ‘homicide’ refers to the act of killing another person • Homicide is often the most investigated death, therefore making it the most autopsied

13. Suicide • The act of ending ones own life • These autopsies often easily identify source, cause, and other factors of the death • Suicide is often identified in the forensic autopsy as a cause of toxic, firearms, blunt force trauma, etc

14. Undetermined Death • In some jurisdictions, the Undetermined category may include deaths in absentia, such as deaths at sea and missing persons declared dead in a court of law; in others, such deaths are classified under "Other"

15. Manner of Death • Consider the following two examples. How would you categorize the manner of death? • A man with a heart condition is attacked and dies from a heart attack during the assault. Is the manner of death accident or homicide? • An elderly woman dies after being kept from receiving proper health care by her son. Is the manner of death natural or homicide?

16. Cause of Death • The pathological condition that produced death • Ex: bludgeoning, shooting, burning, drowning, strangulation, suffocation, hanging, drowning

18. Mechanism of Death • Describes the specific change in the body that brought about the cessation of life • Ex: loss of blood, exsanguination, cessation of brain function

19. Students Will Be Able To: • Explain how the development of rigor, algor, and livor mortis occurs following death. • Use evidence of rigor, algor, and livor mortis to calculate the approximate time of death. • Use evidence from the autopsy’s report on stomach contents to estimate time of death.

20. Time of Death • Generally, time of death is estimated from certain changes that occur in the body following death • Changes can also indicate alterations in the body’s position after death and whether or not the death was murder or suicide

21. Time of Death • Can use the following to estimate time of death • Liver mortis • Rigor mortis • Algor mortis • Stomach content • Ocular changes

22. Livor Mortis • Means death color • As the body decomposes, blood seeps through tissues and settles in the lower parts of the body • RBC’s break down causing hemoglobin to spill out • Hemoglobin turns purple when autolysis occurs • Dark purplish-blue discoloration that is seen on the portions of the body nearest the ground is called postmortem lividity

23. Livor Mortis • Provide clues as to how long a person has been dead • Lividity begins 2 hours after death • After 8 hours, lividity is fixed • Discoloration becomes permanent • If death occurred between 2 and 8 hours, lividity will be present but when the skin is pressed, the color will disappear • Also provides a clue as to what position a person was in when they died • Lets CSI’s know if the body has been moved

24. Livor Mortis • Ambient temperature at which a person dies impacts the time it takes for lividity to set in • If outside on a hot day, livor mortis occurs at a faster rate • If in a cool place, livor mortis occurs at a slower rate • Also affected by anything impeding blood flow such as watches, rings, belts, etc

31. Rigor Mortis • Immediately after death the body is limp due to relaxation of the muscles • Over time the muscles begin to stiffen due to chemical changes within the muscle tissue—this is called rigor mortis • Calcium accumulates in the muscle tissue resulting in muscle fibers remaining in a contracted, rigid position • Rigor begins at the lower jaw and neck and spreads downward

33. Rigor Mortis • Starts within 2 hours after death • Starts in head • After 12 hours, the body is at its most rigid state • Stiffness disappears after 36 hours • Can last as long as 48 hours • Depends on body weight and temperature

34. Rigor Mortis • No visible rigor entails that the individual has been dead less than 2 hours • If body is rigid, then the body has been dead 12 hours • If rigor is only in head, then the person has been dead a little over 2 hours • If there is rigor throughout the body but not in the face, then the body is losing rigor resulting in the individual being dead over 15 hours

36. Rigor Mortis • Factors affecting rigor mortis include • Ambient temperature • Cooler the body, the slower the onset of rigor • Warmer the body, the faster the onset of rigor • Person’s weight • Rigor is slower in a heavier person than in a thinner person • Due to stored oxygen • Type of clothing • Presence of clothes accelerates rigor mortis • Naked body cools faster which slows down rigor

37. Rigor Mortis • Factors affecting rigor mortis include • Illness • If a person dies with a fever, the body temperature will be higher and rigor will set in faster • Level of physical activity before death • If a person was exercising before death, then rigor will progress faster • Sun exposure • A body exposed to direct sunlight will be warmer resulting in rigor to occur faster

43. Algor Mortis • Defined as death heat • Describes the temperature loss in a corpse • Normal temp is 98.6 F • After death body tends to cool • Generally, temp of a dead body averages a drop of approx. 1.5 degrees F per hour.

44. Algor Mortis • To determine the temperature of a corpse, a thermometer is inserted into the liver • Generally, temperature of a dead body averages a drop of approx. 0.78°C (1.4°F) • After 12 hours the body loses about 0.39°C (0.7°F) per hour until the body reaches the same temperature as the surroundings

45. Algor Mortis • Factors affecting algor mortis • Surrounding temperature • Body will lose heat faster in a cooler environment that in a warmer environment • Surrounding air temperature • Heat loss will occur faster in a windy environment • Weight of individual • Excess body fat will slow down algor mortis • Clothing • Presence of clothes will slow down algor mortis

46. Stomach Content • Time of death can be approximated by appearance and amount of stomach contents • It takes 4-6 hours for the stomach to empty its contents in the small intestine and another 12 hours for the food to leave the small intestine

47. Stomach Content • If undigested stomach contents are present, then death occurred 0-2 hours after last meal • If the stomach is empty, but food is found in the small intestine then death occurred at least 4-6 hours after a meal • If the small intestine is empty and wastes are found in the large intestine, then death occurred >12 hours after a meal

49. Ocular Changes • Early postmortem changes occur in the eyes • Buildup of potassium accumulates inside of vitreous humor of eye • Buildup can be used to estimate the time of death • If the eyes stay open, a thin film may form on the corneal surface in a few minutes, and cloudiness in two to three hours • If the eyes remain closed, corneal film may not occur for hours, and cloudiness may take 24 hrs or longer to appear

50. Students Will Be Able To: • Describe the stages of decomposition of a corpse.