1. Unit 8 – Decomposition & Human Remains
Mrs. Teates
Forensic Science
Newport 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 place
Onset is 10 minutes to several hours
Rapid cooling can delay it
Lasts up to 72 hours

4. Chemistry of Rigor Mortis
Living muscle cells use oxygen to burn glycogen
After death no oxygen—anaerobic glycosis makes lactic and pyruvic acids
pH falls as acidity increases
Acid promotes a reaction between actin and myosin which work together to contract the muscle
Muscle shortens until all ATP and acetylcholine is used up

5. Muscle Contraction

6. End of Rigor Mortis
The muscles relax when the body starts to decompose and the fibers begin to break down
Intracellular 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 fibers
Temperature
Stiffen faster at higher temperature
Studies of rigor development in rats

8. Livor Mortis Heart stops beating which had been mixing blood
Red blood cells are denser so they sink
Maroon to blue color develops at lowest points
Visible 30 minutes-2 hours after death
Tells you if the body was moved.

9. Livor Mortis
Soon after death, blood is still in vessels, so pressure on an area pushes the bood out
As time goes on blood vessels break down as do blood cells and hemoglobin break down pigment moves out into the tissues
Pressure or constrictive clothing prevents blood from pooling locally
Contact pallor

10. Livor Mortis

11. Livor Mortis
After death cells release enzyme (fibrinolysins) that prevents clotting
Blood in body stays liquid after death
Permanently 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 contact
faster if in water because enhanced contact
Convection
Wind cools faster
Rate of cooling of body after death
1.5 °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 time
The bigger the temperature difference, the faster the cooling rate
Outdoors, temperature varies a lot—must correct formula by varying Tambient

14. Algor Mortis
If ambient temperature is constant, Newton’s Law of Cooling is easy to solve
Measure temperature at two different times without moving the body to find k

15. Algor Mortis

16. Algor Mortis Clothing Obesity Ratio of surface area to volume
Insulates body from heat loss
Obesity
Fat insulates, temperature falls more slowly
Ratio of surface area to volume
Children, thin people cool faster
In water?
Cooling is faster since water is a better conductor of heat than air

17. Approximate Times for Algor and Rigor Mortis.

18. Algor Mortis
New issue
Is there a plateau before body temperature starts to fall after death?
May be up to several hours
Anaerobic cellular chemistry continues after death
Cellular 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 life
It 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 eye
Time of death
Most accurate in first 12 hours after death
Supposedly independent of temperature

22. Determining Long Post Mortem Intervals
Decomposition occurs in stages
Initial Decay (0-3 days)
Autolysis--body’s own enzymes destroys tissue
Begins immediately
Putrefaction (4-10 days)
Bacteria in gut leak out
Anaerobic conditions
Bloat from hydrogen sulfide, methane, cadaverine, putrescine released

23. The Smell of Death cadaverine putrescine
Breakdown products from amino acids ornithine and lysine
Amino acid loses CO2
H = white C = turquoise N = blue

24. Determining Long Post Mortem Intervals
Black Putrefaction (10-20 days)
Body collapses
Liquid seeps into the soil
Butyric Fermentation (20-50 days)
Cheesy smell from butyric acid
Maggots leave
Beetles arrive
Dry decay (beyond 50 days)
Hair is consumed by moths and mites
Bones are left

25. Longer Term Estimates of Time of Death
Monitoring ratios of body decay products in the soil
Dr. Arpad
Vass, ORNL
The Body Farm
U. Tenn.
The first well controlled experiments to explore decomposition

26. Identifying Small Molecules
Gas chromatography
Presumptive test
Gas chromatography + mass spectrometry
Definitive test
We will discuss these techniques in detail later in the course!

27. Volatile Fatty Acid Analysis Results from the Body Farm
Depends on temperature
The hotter, the faster the reactions proceed
Accumulated Degree Days (sum average daily temp)
Decay is linear in Accumulated Degree Days
Depends on whether body was buried or not
Decay is faster on the surface
More insect activity
Warmer—2 feet down is fairly constant 50-55o F
Decay is slower in acid soil
Pine forests have very acid soil
Decay 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 enzymes
Basic conditions enhance formation
Prominent on cheeks, buttocks, stomach, breasts
Resistant to bacteria
Slows 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, continued
Stage
Description
Initial 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 bloating
The cadaver is swollen by gas produced internally, accompanied by the odor of decaying flesh (4–10 days).
Black putrefaction
Flesh 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 fermentation
Cadaver drying out. Some flesh remains
at 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 Death
Algor Mortis: Body cooling rate
98.4°F – internal body temperature
1.5
Hours since death =
Livor Mortis: skin discoloration caused by pooling of blood
Rigor Mortis: rigidity of skeletal muscles
Temperature of body
Stiffness of body
Time since death
Warm
Not stiff
Not dead more than 3 hours
Stiff
Dead between 3 and 8 hours
Cold
Dead between 8 and 36 hours
Dead for more than 36 hours
A 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:
Taxonomy
Classification of Things in an Orderly Way
We 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 investigation
There are three areas of application:
Insect damage to structures
Infestation of foodstuffs
Insects that inhabit human remains
Forensic Entomology

35. Life Cycle of Insects Metamorphosis egg larva (maggot) pupa
winged adult
The 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 next
Degree day – amount of development that occurs in 24 hours
Accumulated degree day (ADD): a given amount of days that an insect requires to complete its development.
Unique to different species of insects
ADH 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 ADH
Calculate degree days and then multiple by 24. This is an approximate value.

40. Insects of Death
Diptera
First to arrive
Then
Blowflies
Flesh flies
Houseflies
Flies 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, continued
Coleoptera
In rough order of appearance, from within hours to dry decay:
Rove beetle
Sexton beetle
Clown beetle
Dermestid beetle
Hide beetle
Some 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 Metamorphosis
The higher the temperature (within limits), the faster the growth.

43. Habitat
Fly species can vary geographically according to climate, season, and habitat.
Variables Affecting Metamorphosis, continued
Phormia regina
Lucilia illustris
For example, the fly pictured on the left prefers shade; the one on the right, sunlit areas.

44. Collection of Evidence

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 12
Forensic 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:
Age
Sex
Race
Approximate height
Cause of death
Forensic Anthropology
Kendall/Hunt

47. Osteology Osteology is the study of bones.
Chapter 12
Osteology is the study of bones.
There are 206 bones in an adult human.
Function of bones:
Provide structure and rigidity
Protect soft tissue and organs
Serve as an attachment for muscles
Produce blood cells
Serve as a storage area for minerals
Can detoxify the body by removing heavy metals and
other foreign elements from the blood
Osteology
Kendall/Hunt

48. Classifying Bones
Long bones – longer than they are wide; include bones in the arms, legs, hands, and feet
Short bones – approximately as long as they are wide; they are found in the wrist and ankle
Flat bones – Flat and enclose soft organs; they include most bones in the skill and the scapula, sternum, hip bones, and ribs
Irregular bones – irregularly shaped; they include the vertebrae and some of the bones in the skull

49. Identifying Bones
Use 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 12
Determining Height of an Individual
The 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 Height
Male Height, H
H = femur 
H = tibia 
H = humerus 
H = radius 
Female Height, H
H = femur 
H = tibia 
H = humerus 
H = radius 
Kendall/Hunt

52. Age Determination Most accurate estimations are made from: Teeth
Chapter 12
Age Determination
Most accurate estimations are made from:
Teeth
Epiphyses or growth plates
Pubic symphysis
Cranial sutures: The three major cranial sutures appear as
distinct lines in youth and gradually close from the
inside 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 12
Sagittal suture completely closed
Male—26 or older
Female—29 or older
Sagittal suture completely open
Male—less than 32
Female—less than 35
Complete closure of all three major sutures
Male—over 35
Female—over 50
Age Determination Using Cranial Sutures
Sagittal suture
Lambodial
Coronal
Kendall/Hunt

54. Age Determination Using Basilar Suture
Chapter 12
Age Determination Using Basilar Suture
Basilar suture
Technically 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 12
In 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 separate
Stage 3: partial union; the epiphysis is attached, but a line is visible
Stage 4: complete union; the epiphysis is attached and a line is not visible
Age Determination
Kendall/Hunt

56. The Medial Clavicle in Stages 1–4
Chapter 12
The Medial Clavicle in Stages 1–4
Stage of Union
of Medial Clavicle
Male
Female
Non-union without separate epiphysis
21 or younger
20 or younger
Non-union with separate epiphysis
16–21
17–20
Partial union
17–30
17–33
Complete union
21 or older
20 or older
Kendall/Hunt

57. Gender Differences in Bones
Chapter 12
Determination of Sex
Gender Differences in Bones
Determination 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 12
A. The female (top) has a wider pubic body than the male (bottom).
Gender Identification
B. The female has a wider subpubic concavity or subpubic angle.
C. Most females have a ventral arc present.
Kendall/Hunt

59. Chapter 12
Human Remains
Male Female
Subpubic Angle 18
Kendall/Hunt

60. Chapter 12
Determine 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 12
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.
Gender Differences
Kendall/Hunt

63. Chapter 12
Determining Race
Race 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 descent
Negroid—African, Aborigine, and Melanesian descent
Mongoloid—Asian, Native American, and Polynesian descent
Race
Caucasoids—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 12
What differences do you notice among these three skulls? Can you determine race?
Kendall/Hunt

65. Odontology The Study of Teeth
Chapter 12
Using Teeth to Determine Identity
Odontology The Study of Teeth
The 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 12
Facial Reconstruction
After 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 Restoration
Kendall/Hunt

67. Steps in Facial Reconstruction
Chapter 12
Steps in Facial Reconstruction
Model 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 12
Animal Facial Restoration
Determining 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 12
Forensic experts may be called upon
to give information on the life and death
of humans and animals in unique
circumstances, including:
More Applications
Mass 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 Farm
The 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 12
Case Study
Case Study: Facial Reconstruction
John 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 12
Anthropologist at Work
This anthropologist is
hard at work dusting
away material from
these embedded bones.
Picture taken at
Chicago’s Museum
of Natural History
Kendall/Hunt