Presentation on theme: "Unit 8 – Decomposition & Human Remains"— Presentation transcript:
1 Unit 8 – Decomposition & Human Remains Mrs. TeatesForensic ScienceNewport High School
2 Lesson 1 – Stages of Death Lesson Essential Questions:What are the stages of death?Vocabulary:Algor mortis, glaister equation, livor mortis, rigor mortis, autolysis, putrefaction, adipocere, saponification, diagenesis
3 Rigor Mortis Skeletal muscles partially contract Joints stiffen, lock in placeOnset is 10 minutes to several hoursRapid cooling can delay itLasts up to 72 hours
4 Chemistry of Rigor Mortis Living muscle cells use oxygen to burn glycogenAfter death no oxygen—anaerobic glycosis makes lactic and pyruvic acidspH falls as acidity increasesAcid promotes a reaction between actin and myosin which work together to contract the muscleMuscle shortens until all ATP and acetylcholine is used up
6 End of Rigor MortisThe muscles relax when the body starts to decompose and the fibers begin to break downIntracellular digestive enzymes are released from the lysosomes as the cells begin to disintegrate, destroying the muscle fibers (autolysis)Meat is more tender after rigor mortis has passed (Aged Beef?)
7 Temperature Dependence of Rigor Mortis Rigor depends on:the type of muscle fibersTemperatureStiffen faster at higher temperatureStudies of rigor development in rats
8 Livor Mortis Heart stops beating which had been mixing blood Red blood cells are denser so they sinkMaroon to blue color develops at lowest pointsVisible 30 minutes-2 hours after deathTells you if the body was moved.
9 Livor MortisSoon after death, blood is still in vessels, so pressure on an area pushes the bood outAs time goes on blood vessels break down as do blood cells and hemoglobin break down pigment moves out into the tissuesPressure or constrictive clothing prevents blood from pooling locallyContact pallor
11 Livor MortisAfter death cells release enzyme (fibrinolysins) that prevents clottingBlood in body stays liquid after deathPermanently won’t clot minutes after death
12 Algor Mortis Body cools by Rate of cooling of body after death Radiation(the higher the body temperature the more heat lost)Conduction depends on surface contactfaster if in water because enhanced contactConvectionWind cools fasterRate of cooling of body after death1.5 °F per hour under “normal conditions”No real conditions are “normal”
13 Algor Mortis Ambient temperature Newton’s Law of Cooling T is body temperature, t is timeThe bigger the temperature difference, the faster the cooling rateOutdoors, temperature varies a lot—must correct formula by varying Tambient
14 Algor MortisIf ambient temperature is constant, Newton’s Law of Cooling is easy to solveMeasure temperature at two different times without moving the body to find k
16 Algor Mortis Clothing Obesity Ratio of surface area to volume Insulates body from heat lossObesityFat insulates, temperature falls more slowlyRatio of surface area to volumeChildren, thin people cool fasterIn water?Cooling is faster since water is a better conductor of heat than air
18 Algor MortisNew issueIs there a plateau before body temperature starts to fall after death?May be up to several hoursAnaerobic cellular chemistry continues after deathCellular chemistry releases energy as heat
19 Testing Potassium Levels in the Eye to Determine Time of Death K concentration is higher inside cells by up to 40X during lifeIt takes energy (ATP) to maintain the difference
20 Maintaining Concentration Difference in a Living Cell
21 Potassium in Ocular Fluid At death, no more ATP formation (energy storage molecule)K diffuses out of cells at a constant rate, into fluid inside the eyeTime of deathMost accurate in first 12 hours after deathSupposedly independent of temperature
22 Determining Long Post Mortem Intervals Decomposition occurs in stagesInitial Decay (0-3 days)Autolysis--body’s own enzymes destroys tissueBegins immediatelyPutrefaction (4-10 days)Bacteria in gut leak outAnaerobic conditionsBloat from hydrogen sulfide, methane, cadaverine, putrescine released
23 The Smell of Death cadaverine putrescine Breakdown products from amino acids ornithine and lysineAmino acid loses CO2H = white C = turquoise N = blue
24 Determining Long Post Mortem Intervals Black Putrefaction (10-20 days)Body collapsesLiquid seeps into the soilButyric Fermentation (20-50 days)Cheesy smell from butyric acidMaggots leaveBeetles arriveDry decay (beyond 50 days)Hair is consumed by moths and mitesBones are left
25 Longer Term Estimates of Time of Death Monitoring ratios of body decay products in the soilDr. ArpadVass, ORNLThe Body FarmU. Tenn.The first well controlled experiments to explore decomposition
26 Identifying Small Molecules Gas chromatographyPresumptive testGas chromatography + mass spectrometryDefinitive testWe will discuss these techniques in detail later in the course!
27 Volatile Fatty Acid Analysis Results from the Body Farm Depends on temperatureThe hotter, the faster the reactions proceedAccumulated Degree Days (sum average daily temp)Decay is linear in Accumulated Degree DaysDepends on whether body was buried or notDecay is faster on the surfaceMore insect activityWarmer—2 feet down is fairly constant 50-55o FDecay is slower in acid soilPine forests have very acid soilDecay is slower if the body is sprayed with insecticide
28 Adipocere—Grave Wax On bodies are not exposed to insects Requires moist anaerobic environment (drowning)Hydrolysis of fat to fatty acids and soaps in presence of bacterial enzymesBasic conditions enhance formationProminent on cheeks, buttocks, stomach, breastsResistant to bacteriaSlows further decomposition
29 Otzi, the Ice Man 5300 year old body Found by hikers in Austrian Alps Otzi is primarily now adipocere
30 Summary of Stages of Death The Process of Death, continuedStageDescriptionInitial or fresh decay (autolysis)The cadaver appears fresh externally but is decomposing internally due to the activities of bacteria present before death (0–4 days).Putrefaction or bloatingThe cadaver is swollen by gas produced internally, accompanied by the odor of decaying flesh (4–10 days).Black putrefactionFlesh of creamy consistency, with exposed body parts black. Body collapses as gases escape. Fluids drain from body. Odor of decay very strong (10–20 days).Butyric fermentationCadaver drying out. Some flesh remainsat first; cheesy odor from butyric acid(20–50 days).Dry decay (diagenesis)Cadaver almost dry; slow rate of decay. May mummify (50–365 days).
31 Summary of Decomposition The Process of DeathAlgor Mortis: Body cooling rate98.4°F – internal body temperature1.5Hours since death =Livor Mortis: skin discoloration caused by pooling of bloodRigor Mortis: rigidity of skeletal musclesTemperature of bodyStiffness of bodyTime since deathWarmNot stiffNot dead more than 3 hoursStiffDead between 3 and 8 hoursColdDead between 8 and 36 hoursDead for more than 36 hoursA pathologist estimates time of death from these factors.
32 Lesson 2 – Forensic Entomology Lesson Essential Questions:How is the life cycle of insects important in determining the time of death?How do insects play a role in decomposition?Vocabulary:Metamorphosis, molt, instar, oviposition, ambient, mites, eclosion, degree-day, puparia
33 We are interested in the phylum, Arthropoda; class, Insecta; order: TaxonomyClassification of Things in an Orderly WayWe are interested in the phylum, Arthropoda; class, Insecta; order:Diptera (flies)Coleoptera (beetles)
34 Entomology is the study of insects. Forensic entomology involves the use of insects and other arthropods to aid in legal investigationThere are three areas of application:Insect damage to structuresInfestation of foodstuffsInsects that inhabit human remainsForensic Entomology
35 Life Cycle of Insects Metamorphosis egg larva (maggot) pupa winged adultThe life cycle of Musca domestica
36 Insects arrive at a decomposing body in a particular order (succession) and then complete their life cycle based on the surrounding temperature. By collecting and studying the types of insects found on a body and their metamorphic stage, a forensic entomologist can estimate the time of death.Time of Death
37 Accumulated Degree Hours and Days Accumulated degree hour (ADH): a given amount of thermal energy needed to develop from one stage of an insect life cycle to the nextDegree day – amount of development that occurs in 24 hoursAccumulated degree day (ADD): a given amount of days that an insect requires to complete its development.Unique to different species of insectsADH and ADD are calculated from temperature data.
38 Calculating ADD Calculate the mean (average) temperature for that day. Compare the mean to the organism’s lower developmental threshold.If the mean is three degrees higher than the lower developmental threshold, then there have been three degree-days.(Developmental thresholds need to be looked up for individual insects.)
39 Calculating ADHCalculate degree days and then multiple by 24. This is an approximate value.
40 Insects of DeathDipteraFirst to arriveThenBlowfliesFlesh fliesHousefliesFlies can arrive within minutes. They lay eggs that hatch to maggots. Maggots feed on soft, mushy body parts. More insects arrive to feed on the body and each other.
41 In rough order of appearance, from within hours to dry decay: Insects of Death, continuedColeopteraIn rough order of appearance, from within hours to dry decay:Rove beetleSexton beetleClown beetleDermestid beetleHide beetleSome beetles feed on the corpse, some on maggots, some on other beetles.
42 The higher the temperature (within limits), the faster the growth. Variables Affecting MetamorphosisThe higher the temperature (within limits), the faster the growth.
43 HabitatFly species can vary geographically according to climate, season, and habitat.Variables Affecting Metamorphosis, continuedPhormia reginaLucilia illustrisFor example, the fly pictured on the left prefers shade; the one on the right, sunlit areas.
45 Lesson 3 – The Skeleton & Skeletal Remains Lesson Essential Questions:Why is it important for forensic scientists to know the bones of the human skeleton?Vocabulary:Forensic anthropology, osteology, oseons
46 Forensic Anthropology Chapter 12Forensic anthropology is a type of applied anthropology that specializes in the changes and variations in the human skeleton for the purpose of legal inquiry.A forensic anthropologist may provide basic identification information on skeletonized or badly decomposed remains.From a whole bone or part of a bone, the scientist may be able to determine:AgeSexRaceApproximate heightCause of deathForensic AnthropologyKendall/Hunt
47 Osteology Osteology is the study of bones. Chapter 12Osteology is the study of bones.There are 206 bones in an adult human.Function of bones:Provide structure and rigidityProtect soft tissue and organsServe as an attachment for musclesProduce blood cellsServe as a storage area for mineralsCan detoxify the body by removing heavy metals andother foreign elements from the bloodOsteologyKendall/Hunt
48 Classifying BonesLong bones – longer than they are wide; include bones in the arms, legs, hands, and feetShort bones – approximately as long as they are wide; they are found in the wrist and ankleFlat bones – Flat and enclose soft organs; they include most bones in the skill and the scapula, sternum, hip bones, and ribsIrregular bones – irregularly shaped; they include the vertebrae and some of the bones in the skull
49 Identifying BonesUse the worksheet to identify the major bones in the body.
50 Lesson 4 – Determination of Characteristics from Remains Lesson Essential Questions:How can sex, gender, age, and race be determined from the skeleton?Vocabulary: femur, tibia, humerus
51 Determining Height of an Individual Chapter 12Determining Height of an IndividualThe height of a person can be calculated by measuring the length of certain long bones, including the femur, tibia, humerus, and radius.Below are the equations used to determine average measurements for both male and female. (All measurements are in centimeters.)Estimation of HeightMale Height, HH = femur H = tibia H = humerus H = radius Female Height, HH = femur H = tibia H = humerus H = radius Kendall/Hunt
52 Age Determination Most accurate estimations are made from: Teeth Chapter 12Age DeterminationMost accurate estimations are made from:TeethEpiphyses or growth platesPubic symphysisCranial sutures: The three major cranial sutures appear asdistinct lines in youth and gradually close from theinside out.Investigators always use an age range because of the variation in people and how they age.The investigator does not want to eliminate any possibilities for identification.Kendall/Hunt
53 Age Determination Using Cranial Sutures Chapter 12Sagittal suture completely closedMale—26 or olderFemale—29 or olderSagittal suture completely openMale—less than 32Female—less than 35Complete closure of all three major suturesMale—over 35Female—over 50Age Determination Using Cranial SuturesSagittal sutureLambodialCoronalKendall/Hunt
54 Age Determination Using Basilar Suture Chapter 12Age Determination Using Basilar SutureBasilar sutureTechnically known as the synchondrosis spheno-occipitalis, closes in females as young as 14 and in males as young as 16. If the suture is open, the individual is generally considered to be 18 or younger.Kendall/Hunt
55 Chapter 12In long bones, the diaphysis makes up most of the bone’s length.The epiphyses are found at the ends of the bones; their function is to allow for growth. (Good places to estimate changes in age.)Though all people are different there are similarities that allow for generalizations in estimating age.Stage 1: no epiphysis (the growth plate has not formed yet)Stage 2: non-union; the epiphysis and bone are separateStage 3: partial union; the epiphysis is attached, but a line is visibleStage 4: complete union; the epiphysis is attached and a line is not visibleAge DeterminationKendall/Hunt
56 The Medial Clavicle in Stages 1–4 Chapter 12The Medial Clavicle in Stages 1–4Stage of Unionof Medial ClavicleMaleFemaleNon-union without separate epiphysis21 or younger20 or youngerNon-union with separate epiphysis16–2117–20Partial union17–3017–33Complete union21 or older20 or olderKendall/Hunt
57 Gender Differences in Bones Chapter 12Determination of SexGender Differences in BonesDetermination of sex is crucial to the analysis of unidentified human remains.The pelvis offers the most definitive traits.Comparison of three characteristics of the os pubis gives the information used to identify sex.Kendall/Hunt
58 Gender Identification Chapter 12A. The female (top) has a wider pubic body than the male (bottom).Gender IdentificationB. The female has a wider subpubic concavity or subpubic angle.C. Most females have a ventral arc present.Kendall/Hunt
60 Chapter 12Determine which are male and which are female. On page 420 in the textbook.Kendall/Hunt
61 Other ways to determine sex of the individual The rib cage and shoulders of males are generally wider and larger than those of females.In addition, about one person in 20 has an extra rib.This is more common in males than in females.In males, the index finger is sometimes shorter than the third finger. In females, the index finger is sometimes longer than the third finger. This is not often used as an indicator of gender, as there are many exceptions.
62 In addition, about one person in 20 has an extra rib. Chapter 12The rib cage and shoulders of males are generally wider and larger than those of females.In addition, about one person in 20 has an extra rib.This is more common in males than in females.Gender DifferencesKendall/Hunt
63 Chapter 12Determining RaceRace is difficult to determine from most skeletal remains, especially since pure races are becoming uncommon.An experienced forensic anthropologist can generally place skulls into one of three groups:Caucasoid—European, Middle Eastern, and Indian descentNegroid—African, Aborigine, and Melanesian descentMongoloid—Asian, Native American, and Polynesian descentRaceCaucasoids—have a long, narrow nasal aperture, a triangular palate, oval orbits, narrow zygomatic arches, and narrow mandibles.Negroids—have a wide nasal aperture, a rectangular palate, square orbits, and more pronounced zygomatic arches. The long bones are longer, and have less curvature and greater density.Mongoloids—have a more rounded nasal aperture, a parabolic palate, rounded orbits, wide zygomatic arches, and more pointed mandibles.Kendall/Hunt
64 Chapter 12What differences do you notice among these three skulls? Can you determine race?Kendall/Hunt
65 Odontology The Study of Teeth Chapter 12Using Teeth to Determine IdentityOdontology The Study of TeethThe identity of an individual can be determined by comparing a person’s teeth to his or her dental records.Unusual features including the number and types of teeth and fillings, the spacing of the teeth, and/or special dental work help to make a positive identification.Teeth are often used for body identification because:They are the hardest substances in the body (they do not readily decompose).They are unique to the individual.X rays are a good record of a person’s teeth, giving them a unique identity.Kendall/Hunt
66 Facial Reconstruction Chapter 12Facial ReconstructionAfter determining the sex, age, and race of an individual, facial features can be built upon a skull to assist in identification.Erasers are used to make tissue depths at various points on the skull.Clay is used to build around these markers, and facial features are molded.Facial RestorationKendall/Hunt
67 Steps in Facial Reconstruction Chapter 12Steps in Facial ReconstructionModel muscles on skull. Add fatty tissue around eyes and lacrimal glands. Add eyelids. Add the nose. Add the parotid gland. Add the ears. Cover all with layers of skin. Detail the face.With a skull: Establish age, sex, and race. Plot landmarks for tissue thickness. Plot origin and insertion points for muscles. Plot landmarks for facial features. Select a dataset and mount markers for tissue thickness. Mount the eyes.Kendall/Hunt
68 Animal Facial Restoration Chapter 12Animal Facial RestorationDetermining what T. Rex looked like using the bone formation.From this: To this:Kendall/Hunt
69 More Applications Forensic experts may be called upon Chapter 12Forensic experts may be called uponto give information on the life and deathof humans and animals in uniquecircumstances, including:More ApplicationsMass murder (Oklahoma bombing, plane crashes, World Trade Center)Earlier man (mummies, Iceman, Lindow Man)Historical significance (Holocaust, uncertain death of famous people)Prehistoric animals (dinosaurs)The Body Farm was created to help forensic experts with this task.Kendall/Hunt
70 The Body FarmThe Body Farm is the nickname of a two-and-a-half-acre research facility in Tennessee developed in 1980 by Bill Bass where bodies are placed in various conditions and allowed to decompose.Its main purpose is to observe and understand the processes and timetable of postmortem decay.Over the years it has helped to improve the ability to determine “time since death” in murder cases.Hic locus est ubi mortui viveuntes docent.“ This is the place where the dead teach the living.”
71 Case Study: Facial Reconstruction Chapter 12Case StudyCase Study: Facial ReconstructionJohn List killed his entire family, moved to a new town, and assumed a new identity. Seventeen years later, Frank Bender reconstructed what he believed List would look like. The reconstruction was shown on America’s Most Wanted, and he was turned in by the viewers almost immediately looking very much like the reconstruction.Check out more about this story on truTV’s Crime Library:Kendall/Hunt
72 Anthropologist at Work Chapter 12Anthropologist at WorkThis anthropologist ishard at work dustingaway material fromthese embedded bones.Picture taken atChicago’s Museumof Natural HistoryKendall/Hunt