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Forensic Pathology , forensic medicine .
- 1. Forensic Pathology Ms. Faulconerand Dr. Walker
- 2. Terminology • Autopsy –The postmortem evaluation of a human body – Postmortem – “after death” – “Autos” – self, “Optos” – seen (Greek) • Necropsy – The postmortem evaluation of an animal – “nekros”- corpse (Greek) Write bold !
- 3. Pathology • Field ofmedicine related to diagnosis of disease – Forensic pathology - Focuses on determining the cause of death by examining a corpse • Requires an M. D. degree plus residency in pathology (total time after high school > 12 years) • Most pathologists do not see patients (at least not live ones) Write all !
- 4. What makes agood pathologist? • A talent for and interest in science. This should include not only biology, but physics, chemistry, and the social sciences (anthropology and psychology). For the bread-and-butter technical part of your work, you should especially have a good grasp of spatial relationships. (geometry, anyone?) • Good communication skills. You will not only be interacting with law officers, but you'll be trying to convince judges and juries that your findings are valid. • Strong stomach. You'll be routinely dealing with dismembered and/or rotting bodies. From a pure visceral standpoint there is no job more disgusting than forensic pathology.
- 5. What makes agood pathologist? • Thick skin. You will be periodically raked over the coals by the local media, who apparently cannot to resist the urge to armchair-quarterback your work. You will also make many enemies among the citizenry. For instance, when you determine that Daddy killed himself, and he wasn't poisoned by that blond bimbo who was only interested in his money, you are going to have some very angry children buzzing around you. • The mind of a detective. You will have to constantly be on guard against being fooled by malefactors smarter and more focused than you. You will have to have some insight into the heart and mind of a criminal.
- 6. Autopsy • Internal andExternal Examination of the body after death – Document disease/injuries – Determine time since death (PMI) – Determine cause/manner of death • Cause: specific reason person died (e.g. gunshot wound to the head) • Manner: Categories (homicide, accident, suicide, natural, undetermined) Write all !
- 7. Autopsy • Internal andExternal Examination of the body after death –Determine mechanism of death • Physiological reason for death (shock, blood loss, asphyxia) –Establish identity Write all !
- 8. Steps • 1st - ExternalExamination – height/weight – Photography – UV exam (fluids) • 2nd - Toxicology – Nail scrapings – Fluid samples – Analysis (GC/MS) • 3rd - Internal Examination – Head (circular saw) – Chest (Y incision) – Abdomen * Inspect organs and weigh Write all !
- 9. Steps of anAutopsy • First step: Examination of the exterior of the body – Records are made of height, weight, and any visible characteristics – Photographs are taken from every possible angle and the body is examined by UV light (find UV active fluids)
- 10. Steps of anAutopsy • Second step – Blood, hair, urine, and oral swab samples are taken – Nail scrapings are collected and the body is X- rayed – Samples may be analyzed by GC-MS (toxicology screening)
- 11. Steps of anAutopsy • Third Step – The pathologist makes a Y incision with a scapel; from each shoulder to midchest, then from midchest to pelvis. – An incision is made across the skull from ear to ear. The skin is pulled back and the bone is cut with a vibrating saw.
- 12. Steps of anAutopsy • Third Step – The brain and major organs (heart, liver, kidneys, spleen) are removed, weighed, tissue samples taken and analyzed. – Stomach contents may be analyzed if present. – The neck and windpipe are examined for abnormalities. – After the examination, the organs are put back in the body and the body is sewn back together (for burial).
- 16. Macroscopic Analysis • COpoisoning – Cherry red coloring • Defense Wounds – Wounds on palms from holding up hands when attacked Write all !
- 17. Macroscopic Analysis • Organs –Polycystic kidneys (top right) – Tuberculosis (lungs) (low right) – Stroke aka infarction (below) Write all !
- 18. Microscopic Analysis • FatEmbolism – Long bone trauma – Burns – Severe soft tissue trauma • Shaken Baby Synd. – Torn axons Write bold !
- 19. PMI • Post-Mortem Interval –The time elapsed since death – Can be determine scientifically & non-scientifically • Traditional Methods: – Algor Mortis – Livor Mortis – Rigor Mortis • Nontraditional methods: – Entomology Write all !
- 20. Algor Mortis • Coolingof the body – Body temperature = 37 Celsius (98.6 Farenheit) – Basic Formula for Time of Death: • Body cools one degree/hour after death • 37 – Body Temperature Postmortem = Hours after death • Temperature measured by liver or rectum Write all !
- 21. Factors Affecting AlgorMortis • Indoors/Outdoors • Clothing or lack thereof – Multiple layers slow cooling – If naked, cooling is faster • If outdoors – Weather conditions • Cold, wind, moisture accelerate body cooling Write all !
- 22. Livor Mortis • Discolorationdue to blood settling • Lividity= degree of discoloration Write all !
- 23. Livor Mortis • Oncethe heart stops pumping blood will pool in the area of the body closest to the ground. • Begins to appear 6-10 hours after death and is fixed after 24 hours • May not be fixed if the body is moved within the first 12 hours after death • A forensic pathologist can use this information to determine whether the body has been moved and to get some idea of TOD. Write bold !
- 24. Rigor Mortis • Stiffeningof the muscles of the body. – Occurs due to buildup of lactic acid in the muscles postmortem, inability of muscles to pump calcium out of the cell – Rigor starts in the small muscles of the face and progresses to the neck , upper extremities, trunk and lower extremities Write bold !
- 25. Rigor Mortis • RigorMortis is usually complete after 36 hours and muscles permanently relax • Rigor mortis is unreliable by itself • Affected by – Drug use – Exertion prior to death Write all !
- 26. Petechial Hemmhoraging • Pinpointred mark that is a sign of manual strangulation, hanging, or smothering • Occurs when blood leaks from capillaries in eyes – Occurs in eyes and on eyelids Write all !
- 28. Forensic Entomology • Typicallyrequires a Ph. D. in Entomology, followed by additional training in forensic applications. Write all !
- 29. Circle Of Life… •Bacteria colonize corpses first – Tolerant of acidic conditions postmortem – Already present in body before death – Activity neutralizes tissues Write all !
- 30. Circle Of Life •Flies show up next – Bacterial activity neutralizes and moistens flesh, which can then be eaten by flies – Flies lay eggs, life cycles continue until moist flesh is consumed Write bold !
- 31. Circle of Life •Beetles/Mites – Some species eat fly larvae, so they’ll show up where the flies are – Can consume drier flesh – Hide beetles – can consume keratin, present in hair and nails Write all !
- 32. Circle Of Life •Wasps – Lay eggs inside and eat fly pupae Write all !
- 33. What can bugstell us? • Urban species in a rural environment or vice versa can indicate that the body has been moved from one setting to another. • Skuttle flies – reproduce underground • Blow flies – reproduce above ground – The presence of Skuttle fly larva on a body found on the surface may indicate a previous burial. Likewise blowfly larvae on a buried body may indicate burial after some time on the surface. Write bold !
- 34. What can bugstell us? • Lack of insect activity can indicate storage at freezing temperatures or enclosure in an air tight container • Sealing a body in a plastic garbage bag, a vehicle, a rug and/or burning it does not deter colonization Write all !
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- 36. Anthropology • The studyof humans and it consists of several sub-fields: – Physical anthropology — the study of the primate order, past and present, such as primate biology, skeletal biology, and human adaptation – Cultural and linguistic anthropology — the study of the aspects of human society and language, past and present – Archaeology — the study of past cultures via material remains and artifacts Write bold
- 37. Forensic Anthropology • Drawspredominantly from the field of physical anthropology – Osteology – the study of bones • Most are Ph. D’s who work primarily as professors • “In those cases in which soft tissue has been degraded by time, temperature, environment or other external forces, the only tissue remaining more or less intact is bone.” http://www.trutv.com/library/crime/criminal_mind/forensics/anthropology/1.html Write bold
- 38. Forensic Anthropologist • Calledinto a crime scene when: – Remains are found during archeological excavation – Remains are badly burned or decomposed – Skeletonized remains are found Write all !
- 39. Identifying Factors • Providelaw enforcement with a biological profile of the deceased – Age – Sex – Ancestry – Stature (Height, body type) – Previous trauma (injuries) – Potential Cause of Death • This helps narrow down the possible identity of the decedent. Write all !
- 40. Age Determination • Olderadults can have the following: – Calcium and other mineral deposits – Changes in the pelvis or evidence of bone diseases like arthritis • Bones become less dense with age – Other clues come from the developmental stages in the teeth and from worn areas in enamel. Write all !
- 41. Age Determination • Lookingat the teeth can reveal the age if the remains belong to a child or adolescent. • Human teeth break through in a predictable pattern and offer a fairly reliable estimate between five months and 21 years. – Baby teeth (20) vs. permanent teeth (32) – Presence or absence of wisdom teeth (usually > 15 y.o.) Write all !
- 43. Age Determination • Theyoung – The epiphyseal union -- areas of the femur that gradually fuse as a person ages -- can help estimate young ages if the teeth are missing. Write all !
- 44. Physical Characteristics • HeightDetermination – Rule of thumb: Height = 5 x Humerus length – Formulas for height based on other major bones as well (spine, tibia, and femur). Write all !
- 45. Ethnicity • Ethnicity canbe determined from variations in the facial structure, especially the nose and eye sockets. – In people of African and Asian descent, the nose ridge is broader than in Caucasians. http://www.internetlooks.com/nasalbonecharacteristicstypical.jpg Write all !
- 47. Physical Characteristics • GenderDetermination: Pelvis – Female pelvic girdle is wider than a man’s. Write all ! Female pelvis Male pelvis
- 48. What can theyfigure out? • In skeletal trauma analysis, some forensic anthropologists can accurately determine: – Degree of force (sharp, blunt, ballistic) • Cuts from a knife • Bullet holes • Fracture from blunt object – Evidence of poisoning – When the blow occurred (before, near, or after T.O.D.) Write all !
- 49. Determining Postmortem Interval •Postmortem Interval – Determining time since death • As bodies decompose, they leak five fatty acids -- the breakdown products of muscle and fat -- into the ground. • Concentration and identity of acids – Can reveal time since death – Can reveal how long the body has been in a location Write all !
- 50. Determining Postmortem Interval •The first technique traces the ratio of the five fatty acids in comparison to each other -- a method that works as long as there is soft tissue (skin and organs) on the body. • If not, another technique tracks the ratios of seven inorganic compounds, such as sodium and calcium, which leach into the soil from the bones. • If a body is too badly decomposed for those techniques, scientists rely mostly on bones.
- 51. Determining Postmortem Interval •If the surrounding soil does not contain the chemicals released as a body decays, the body was probably placed there recently. • Soil samples containing those chemicals and the bugs that help experts guess how long it has been since the person died. This number can be the key to whether an alibi flies or flops in a murder trial.
- 52. Determining Postmortem Interval •Temperature, humidity levels, and grave depth can all change how fast a body decomposes. • The fastest transformation from corpse to skeleton happened in just 12 days. Write bold !
- 53. Determining Postmortem Interval •Total skeletonization occurs in: – Buried two feet: six months – Buried six feet: two years • A body will skeletonize faster if it is buried in acidic ground. – Soil in pine forests tend to be far more acidic than soil in deciduous forests. Write bold !
- 54. Stages of Decomposition •Living Organism – No outward decomposition – Contains microorganisms that will rapidly multiply after death
- 55. Stages of Decomposition Stage1 – Initial Decay - 0 to 3 days postmortem Write all !
- 56. Stages of Decomposition •Stage 2 – Putrefaction – 4 to 10 day postmortem • The pig has become bloated from the build up of gases within the body. • Gas buildup creates internal pressure, inflating the body and forcing fluids from the body. Write all !
- 57. Stages of Decomposition •Stage 3 - Black putrefaction – 10 to 20 days postmortem • The pig's body has collapsed with black exposed surfaces and creamy flesh Write bold !
- 58. Stages of Decomposition •Stage 4 – Butyric Fermentation – 20 to 50 days postmortem Write all !
- 59. Stages of Decomposition •Stage 5 – Dry Decay – 50 to 365 days postmortem Write all !
- 60. Case Study • Aman kills his wife. His girlfriend watches as he places the body in a 55-gallon drum, douses it with kerosene and lights a match. • He dumps the scorched contents onto the edge of an empty field. Three years later, the couple splits. The woman goes to the police and describes the murder. Investigators find no trace of a crime at the scene.
- 61. Case Study • Theytest the soil and find nothing. But one of the investigators has an idea: He saws off a limb from a tree on the edge of the field and traces the tree's annual growth rings back three years. • In the lab, he is able to isolate kerosene within that ring. • The suspect is convicted although a body is never found.
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Editor's Notes
- #39 Gender — The male pelvis is narrower than the female, and certain features of the skull are larger in males; the bones tend to be heavier as well. Age — In younger people, the stages at which bones are uniting show advancing age; for older people, calcium and other mineral deposits help as well, along with successive changes in the pelvis or evidence of bone diseases like arthritis; other clues come from the developmental stages in the teeth and from worn areas in enamel. Previous trauma — If a bone was broken and there are hospital records, this can help with identification. Race — One of three races can be determined from variations in the facial structure, especially the nose and eye sockets. In Negroids and Mongoloids, the nose ridge is broader than in Caucasians. Height — An intact corpse can be measured, but a disarticulated or incomplete skeleton has to be pieced together. One rule of thumb is that height is about five times the length of the humerus, but there are formulas for height based on other major bones as well (spine, tibia, and femur). Body type — Tables provide an estimate based on bone characteristics for determining whether the person was slender, of medium build, or heavy. Cause of death — This might be evident in the skull or some of the bones: a knife cut, bullet holes, a blunt weapon fracture, or even a saw to dismember the bones. Sometimes bones will yield evidence of poisoning as well