Pathology

1. Pathology

2. Pathology • Early forensic scientists were physicians who were called upon to give an opinion as to the cause of death in individuals. • Increasingly in the US, medical examiner programs are replacing the old system of elected coroners, who are not required to have training.

3. Pathology • First state medical examiner system was established in 1939 in Maryland to assist in identification of decent, to determine the time of death, to conduct the autopsy, and to determine the cause of death. • These topics comprise pathology.

4. PathologyIdentification of Decedent • Regardless of who has the ultimate legal burden, the coroner or medical examiner works with law enforcement personnel & others to help identify the bodies of deceased persons. • Few forensic endeavors offer a more challenging & creative exercise than establishing identification of the living or dead.

5. Pathology • Identification is essential to the completion & certification of official documents. • The accurate identification of decedent permits certification of death & notification of next of kin. • To facilitate identification of a corpse, the following procedures are standard:

6. PathologyPhysical Description • A basic portrait parle’ of the person should be given, much as if describing a living person. • Height, weight, color of eyes, hair, etc. should be recorded. Decomposition can affect color of skin & hair. • Skin can blacken to appear Negroid instead of Caucasian.

7. PathologyPhysical Description • Blond hair darkens, while red or brown hair tends to become lighter & gray. • Weight may be overestimated due to bloating. • If hair color is patchy or varies near scalp, dying is a distinct possibility & samples should be taken for lab analysis.

8. PathologyScars & Marks • Part of portrait parle’ are skin markings – birthmarks, scars, etc. • Tattoos may be especially helpful since they may indicate some past experience (such as military insignia), or clue as to lifestyle (“jailhouse” tattooing), sexual preferences, or personal interests, etc. including the decedent’s initials or someone else’s initials.

9. PathologyScars & Marks • Some tattooed numbers are found such as social security, military or prisoner of war. • Irregular scarring may indicate the former presence of a tattoo. • In case of indistinct tattoos, infrared photography, high-contrast photography, & computer image enhancement may be successful.

10. PathologyFingerprints • Fingerprinting is still the mainstay of identification techniques & the basics of taking fingerprints from the deceased in various states of decomposition are in chapter 5. • The new AFIS technology makes it possible for fingerprint identification to be accomplished with increasing speed.

11. PathologyPhotographs • Entire body should be photographed as well as the full face & profile. The profile is particularly valuable in recording the shape of the ear, feature of the face most like a fingerprint, which may be matched to authenticated photograph. • Scars & distinctive features (amputations) should be documented. Photos are shown for possible identification of deceased.

12. PathologyAge Determination • Deceased person’s apparent age may be roughly estimated by teeth & in case of people under 25 the joining of bones. • X-rays provide a basis for studying extent of cranial & epiphyseal fusions (the uniting of various bones serve as landmarks for estimating decedent’s age).

13. PathologyDental Features • Pattern of dental work, including plates, bridges & fillings can be compared with known dental records, plaster olds, & x-rays to effect a positive identification. • Fillings are highly distinctive & can serve as an effective means of individualization.

14. PathologyRadiological Evidence • The presence of old bone fractures, shown in x-rays of the body, sometimes provide a positive identification. • So may surgical pins, plates, pacemakers & other implants.

15. PathologyBlood Factors • Not only do ABO blood grouping, Rh factor & other blood characteristics provide an additional means of identification, but DNA testing makes the blood evidence particularly valuable. • DNA can also be helpful in instances of badly decomposed or skeletonized bodies.

16. PathologyMedical Indications • A thorough postmortem examination may reveal various diseases or conditions that have identification value such as hypertension, old strokes, diabetes, Alzheimer’s disease & drug abuse. • Presence of anticonvulsants indicates a seizure disorder; antidepressants suggest depression, even suicidal circumstances; and so on.

17. PathologyOther Means • Clues to dead person’s identity may be found at scene where body’s discovered or personal effects secured by police or pathologist. • Driver’s license or other identification card in victim’s wallet or purse may be helpful, although mere possession isn’t conclusive. • Monogrammed personal items (cigarette lighter or clothing) may provide clues also.

18. PathologyTime of Death • When body is discovered, pathologist or medical examiner make observations to indicate approximate time of death ASAP! • The sooner after death body is examined, more accurate estimation of time of death. • Time of death is estimated from changes that occur in the body following death. They are…

19. PathologyTime of Death • Temperature, post-mortem lividity, rigor mortis, & putrefaction. Stomach contents & ocular changes may also be helpful in determining time of death. • Temperature: rate of cooling depends on temperature of air, way body is clothed, amount of subcutaneous fat on body. • Temp averages a drop approx. 1 & ½ degrees Fahrenheit per hour.

20. PathologyTime of Death • Lividity: dark purplish-blue discoloration seen on portion of body nearest ground caused by blood settling into body’s lower parts due to gravity. It can determine if a body has been moved after death or not. • Forearms & lower legs darken due to hanging. • Lividity appears bout 2 hours after death when blood tends to clot in tissues.

21. PathologyTime of Death • Rigor Mortis: Immediately after death, body is limp due to relaxation of muscles • After death, body begins to stiffen due to chemical changes within muscle tissue causing rigor mortis beginning at lower jaw & neck & spreads downward. • Time when rigor sets in may be as soon as 15 minutes following death or as long as 15 hours after death.

22. PathologyTime of Death • Average time is 5 to 6 hours after death with upper portion of body affected after about 12 hours and entire body withing some 18 hours. • Rigor mortis disappears usually within 36 hours after death beginning again with head & neck & proceeding to lower body. Disappearance may take from 8 to 10 hours.

23. PathologyTime of Death • Variables that affect speed of rigor’s onset & departure include great heat & individual differences in muscular development. • Rough rules generally employed: • R.M. should begin within 10 hours after death • Whole body should be stiff within 12 to 18 hours after death • Stiffening disappears within 36 hours after death

24. PathologyTime of Death • Under certain conditions stiffening of hands or arms may take place immediately after death known as cadaveric spasm & frequently confused with RM. • It occurs in cases where great tension or excitement precedes death like drowning, suicides, homicides.

25. PathologyTime of Death • Putrefaction: decomposition changes in dead body caused by action of micro-organisms (bacteria). • Characterized by bloating due to gas, darkening of face with decomposition liquids escaping from nose & mouth, tongue swelling, formation of fluid or gas filled blisters, green discoloration of abdominal skin

26. PathologyTime of Death • Temperature can affect putrefaction. Further destruction of body is caused by maggots & various insects. • Flies may deposit eggs between eyelids or lips or in nostrils within matter of minutes. Maggots may develop within 24 hours. • If temp above 40 degrees Fahrenheit, various insects will feed upon the body until it is skeletonized.

27. PathologyTime of Death • Stomach Contents: can also be used to approximate time of death. Emptying rates change depending on number of factors like type & amount of food, intake of drugs or medicine, emotional/medical condition. • Light meal: about 2 hours; Medium meal: about 3 to 4 hours; Heavy meal: about 4 to 6 hours or even more.

28. PathologyTime of Death • Empty stomach means death probably occurred a minimum of 4 to 6 hours previously. If small intestine is empty as well, death probably occurred 12 or more hours earlier. • Ocular Changes: If eyes stay open, a thin film may form on the corneal surface in a few minutes & cloudiness may take 24 hours or longer to appear.

29. PathologyTime of Death • It is important to remember that time of death can only be estimated and that any estimate is subject to error based on environmental and other variables as well as the person determining these variables and making the decisions.

30. PathologyAutopsy • Term postmortem examination refers to all procedures followed by coroner, forensic pathologist, or other qualified individual in conduction a death investigation. • It includes the preliminary examination, identification of the body, photography, x-raying, etc. and the autopsy.

31. PathologyAutopsy • Postmortem warranted & should be conducted in suspected homicide/suicide • A preliminary examination should be conducted by physician in deaths by criminal violence, suicides, accidental deaths, deaths where no physician was present, sudden deaths of a person in good health, prison deaths & deaths that occur in unusual/suspicious manner

32. PathologyAutopsy • When preliminary exam & investigation fail to establish clear cause of death, autopsy should be conducted. • General or medical autopsy performed in a hospital for purpose of discovering any pathological (disease) processes in addition to learning the cause of death. • In contrast, medical-legal autopsy much more complete & requires special training

33. PathologyAutopsy • It includes identifying & tagging corpse, photo-graphing body dressed & nude; full-face & profile portraits; height & weight; taking x-rays; examining external body, providing detailed description of bruises, ligature marks, gunshot or stab wounds, etc.; dissection & examining internal body; lab testing organs & body fluids for drugs & poisons; & rendering opinion, adding “cause of death” to death certificate.

34. PathologyAutopsy • In actual dissection of body, thoraco-abdominal (chest-belly) cavity opened most often with Y-shaped incision beginning at each armpit area & running beneath breasts to lower end of breast-bone continuing downward through middle of abdomen to pubis.

35. PathologyAutopsy • Next, front portion of ribs & breastbone removed as a unit, exposing most of organs for examination. • Next, heart & lungs together with trachea & esophagus are taken out. • Abdomen is given general exam prior to removal of organs. Fluids are aspirated (drawn out) so they can be analyzed.

36. PathologyAutopsy • Each organ is weighed, examined externally, sectioned for internal study. • Any fluid in thoracic pleural cavity (chest lungs) is aspirated for later analysis. • Tissues from organs are mounted on slide for study of cellular changes. • Contents of stomach are measured, recorded, & sampled for toxicological analysis.

37. PathologyAutopsy • In pelvic area, genitalia are examined with regard to any injury or foreign matter. Vaginal & anal swabs are taken during external exam. • Blood, semen, hair samples collected for lab analysis. Urine collected from removal of bladder so certain drugs that tend to concentrate there (Valium & barbiturates) my be detected by toxicologist.

38. PathologyAutopsy • Finally, head is examined beginning with eyes. To remove brain, incision is made across top of head, scalp is pulled forward & skull exposed. • A saw is used to cut through top of skull so brain may be examined, removed (after various nerves, blood vessels & other attachments are cut), weight & section for later microscopic review.

39. PathologyAutopsy • When finished, large incisions are sewn shut. Microscopic specimens are studied, chemical analyses are conducted in lab. • This completes autopsy after which medical examiner synthesizes findings & attempts to determine “cause of death” along with contributing factors.

40. PathologyAutopsy • Results are presented as formal “autopsy protocol”, a legal report & file, typically a folder that includes photographs, x-rays, fingerprints, & toxicological test results. • Report includes: external exam (description of clothing, description & identification of body), evidence of injury (external & internal), central nervous system (head & brain), internal exam of chest, abdomen & pelvis, toxicology test findings, opinion.

41. PathologyCause of Death • For investigative purposes, it is important to distinguish between the cause, manner & mode of death. • Cause of death: pathological condition producing death (subdural hemorrhage) • Manner of death: physical agent or instrument that was employed (blunt-force injury to skull)

42. PathologyCause of Death • Mode of death: indicates intent or lack thereof when instrument was used & by whom (homicide by person(s) unknown). • Possible scenario: Cause – myocardical infarction (heart attack), manner – arteriosclerosis (hardening of arteries), & mode – natural. • 4 modes of death: natural, accidental, homicidal & suicidal.

43. PathologyCause of Death • Findings in autopsy are critical in determining cause of death. Example: Absence of firearm at scene would suggest homicide, while presence of suicide note would, if proved genuine, be an indication of suicide. • “Psychological autopsy”: investigation of decedent’s mental state prior to death conducted as aid to determine if suicide

44. PathologyCause of Death • Asphyxia: death caused by lack of oxygen. In suffocation, passage of air is block such as pillow over face with possible bruises & abrasions inside victim’s upper lip. • Suffocation may be accidental such as by food obstruction of which foreign material should be revealed during the autopsy.

45. PathologyCause of Death • Deaths by strangulation (when homicidal) may be indicated by presence of fingertip bruises on neck. Fingernail marks may be present in manual strangulation. Ligature strangulation will be indicated by presence of groove or other marking on victim’s throat. At autopsy, strangulation may be indicated by fractures of larynx including hyoid bone.

46. PathologyCause of Death • In case of asphyxia by hanging, signs of violence, particularly about the neck, may be an indication of prior strangulation. If body is found not to be completely suspended, death is probably suicide, since murderer would strive to completely suspend body. Hanging is common means of suicide but is relatively rare as form of homicide or accidental death (except in the case of children).

47. PathologyCause of Death • Drowning deaths are also due to asphyxia. Air in lungs replaced by fluid, so victim chokes. Irritation of mucous membranes results in formation of great deal of mucus in throat & windpipe. Efforts to breathe produce a sticky foam which may be mixed with vomit. Foam prevents passage of air into lungs.

48. PathologyCause of Death • Drowning indicated by presence of white foam. Other indicators may be articles found grasped in hand & swelling of lungs. • Asphyxia may be caused by blow to neck, (karate chop) or compression of chest (pinned under collapsed building). Cherry-red lividity may indicate asphyxia by carbon monoxide poisoning & can be determined by autopsy.

49. PathologyCause of Death • Blunt-force Injuries: usually directed at head. Internal organs may suffer without external indication of violence. Blows to head reveal fracture of skull; chest may produce broken ribs that pierce lungs or heart or cause heart to be crushed or ruptures; blows to abdomen may produce ruptured spleen, liver, or kidney & may result in death from hemorrhage.

50. PathologyCause of Death • Burning Deaths: by fire typically cause corpse to assume a distorted position somewhat resembling a boxer’s pose. It occurs if person is alive or dead since effect is simply contracted muscles. If alive, smoke stains around nostrils & carbon monoxide in blood. In case of skin burned without attendance singeing body hair or clothing, scalding by hot liquid or steam is indicated.