1. Human Remains
Forensics Chapter 12

2. Investigating Human Remains
Read pages and answer the following questions with your group
THINK: What features of the skeletal remains can officials use to identify unknown individuals?
What type of specialists do officials consult?

3. Postmortem Interval: Determining the Time of Death
A pathologist usually determines the time of death
Can be done most accurately if the body is found within the first 24 hours of death, using the indicators of algor, livor, and rigor mortis.
After 24 hours, pathologists must use other methods, such as environmental conditions and other information from the scene

4. Postmortem Interval: Determining the Time of Death
Algor mortis refers to the cooling rate of the body after death
As soon as a person dies, the body cannot remain at 98.6ºF and the temperature begins to even out with environment
The Glaister formula can be used from 1-36 hours after death to measure internal body temperature:
h=(98.6ºF- internal temperature)/1.5
Most accurate in first 12 hours
Body cools degrees per hour

5. Postmortem Interval: Determining the Time of Death
Things to consider when determining time of death:
Temperature of environment
Type of clothing on the body
Whether the clothing is wet
Air movements
Layers of clothing
Other surrounding conditions
Body mass (child, adult, etc.)

6. Postmortem Interval: Determining the Time of Death
Livor mortis refers to the pooling of blood in the body after the heart stops, caused by gravity
Appears on skin as purplish, red discolorations which can also indicates position of body at time of death
There will be no livor mortis in areas touching the ground because capillaries are compressed
Begins within a half hour of death and is most evident within 12 hours
Useful in determining if a body has been moved after death

7. Postmortem Interval: Determining the Time of Death
Rigor mortis refers to the rigidity of skeletal muscles after death
As soon as a person dies, the muscles relax, the ATP in the muscles breaks down, fluid concentrations change, and the muscles become rigid
Begins in smaller muscles so it is first seen in face, neck, and jaw
Occurs within two or three hours after death and is gone within approximately 30 hours, leaving the body limp…reverse process

8. Postmortem Interval: Determining the Time of Death
Rigor mortis is also affected by environmental factors:
Temperature
Dehydration
Condition of muscles
Use of muscles prior to death

9. Forensic Anthropology: Skeletal Remains
Anthropology is the study of humankind including anatomy, variability, evolution, and culture
Forensic Anthropology is a type of applied physical anthropology that specializes in the human skeletal system and its changes and variations, for purposes of legal inquiry and ultimately for presentation in courts of law
Uses knowledge of skeletal system to identify crime victims and cause/circumstances of death
Can apply information to cases hundreds-thousands of years old

10. Forensic Anthropology: Skeletal Remains
Forensic anthropologists study skeletons whose identities and circumstances of death are unknown or questionable
They analyze individuals whose bodies have decomposed, were badly burned, or have become mummified or skeletonized
Information gathered from skeletal features is the principal source of information about unidentified individuals

11. Forensic Anthropology: Skeletal Remains
Using forensics, the investigator can often answer many questions:
Are the remains human?
Are the remains a single individual or mixed remains of several individuals
When did the death occur?
Was the body disturbed after death?
What are the gender, age, and race of the individual?
What caused the death?
What kind of death was it?
Did the individual have any anatomical peculiarities, signs of disease, and old injuries?
Can the individual’s height, body weight, and physique be estimated?

12. Human vs. Animal Bones The study of bones is known as osteology
Humans and animals have different skeletal structures, different bones, and differently shaped bones
Human bone can be identified from animal bone through microscopic examination of cellular structures
Bones have holes or osteons to carry blood supply
Animal bones have a regular pattern of osteons whereas humans have irregular patterns.

13. The Skeleton An adult human has 206 bones
The skeleton performs many vital functions
Provides structure and rigidity for the body
It shelters and protects soft tissue and internal organs
Skull surrounds and protects the brain
Sternum and rib cage encase the heart and lungs
Skeleton provides sites for the attachment of muscles, tendons, and ligaments that allow the body to move.
Skeleton also stores minerals and houses sites that produce RBCs.

14. The Skeleton
The body moves through the interactions of muscles and the skeleton
Tendons and ligaments are structurally similar but function differently
Tendons connect muscles to bones
Ligaments connect bone to bone
Joints are points where a muscle is connected to two different bones and contracts to pull them together

15. The Skeleton Marrow in bones produces blood cells
An average of 2.6 billion RBCs are produced each second by the bone marrow to replace those worn out and destroyed by the liver
Marrow also produces the cells of the immune system

16. The Skeleton
Bones serve as a storage area for minerals such as calcium and phosphate
Excess minerals in blood causes buildup in bones
When supplies are low in blood, they are withdrawn from bones to raise levels
Bone tissue can also clean the body by removing heavy metals and other foreign elements from the blood
It stores them and releases them slowly for excretion, lessening any ill effects on nervous tissue

17. The Skeleton
Bones can be classified as long, short, flat or irregular:
Long bones are longer than they are wide
Bones of arms, legs, hands, and feet
Short bones are approximately as long as they are wide
Bones of wrist and ankle
Flat bones are flat and enclose soft organs
Bones of skull, scapula, sternum, hip bone, and ribs
Irregular bones are irregularly shaped
Bones of vertebrae and some bones of skull

18. Stature: Estimating Height Using Long Bones
Forensic scientists can estimate a person’s stature by examining one or more of the long bones
Long bones considered are: femur, tibia, humerus, and radius.
Men and women have different proportions of long bones to total height; therefore, there are different formulas
If complete long bones are available, the formulas can be used to estimate height within a range of ±7.5 centimeters

19. Stature: Estimating Height Using Long Bones
Estimated height of a female (centimeters):
H= femur length x
H= tibia length x
H= humerus length x
H= radius length x

20. Stature: Estimating Height Using Long Bones
Estimated height of a male (centimeters):
H= femur length x
H= tibia length x
H= humerus length x
H= radius length x

21. Activity: Estimating Height
Complete the activity and questions on pages
Work with your group to complete the activity

22. Sex Determination
Determining sex is crucial when analyzing unidentified human remains
The os pubis, sacrum, and ilium of the pelvis are bones that have the most obvious differences between men and women, along with the shape of the skull, shape of the mandible, and the size of the occipital protuberance at the back of the skull to determine male and female traits.

23. Sex Determination Common way to determine male vs. female:
Males tend to have longer bones than females
Males tend to have larger areas of muscle attachment
Sacrum is straighter in females and more curved in males
The space in the middle of the pelvic bone is larger in women to make birthing easier
For a more accurate determination, removal of the os pubis can be used

24. Sex Determination
A forensic anthropologist can make the surest determination of sex by comparing three basic characteristics of the os pubis:
Width of the pubic arch
Width of the pubic body
Existence of a well-defined ventral arc

25. Sex Determination
The pubic arch has a larger angle in the female than in the male
The pubic body is narrower in males than in females
Males do not usually have a ventral arc
Ventral arc is a bony ridge found on the bottom side of the pubic bone that does not usually appear until a woman is in her mid-20s
A small bony line appears in girls around 14
4% of the female population will not show any ventral arc…then other methods are needed

26. Activity: Sex Determination
Please complete the activity on pages
Work with your group to complete the activity

27. Differences in Skull Features
There are several differences between men and women in the sizes and shape of the bones of the skull

28. Determining Age
A forensic anthropologist can reasonably estimate an individual’s age at the time of death by examining biological changes that took place during that person’s life
Examining teeth, bone growth, epiphyses, and closure of cranial sutures
After the growth period of years, age determination becomes difficult

29. Determining Age
All skeletal changes happen at different ages in different individuals
Estimates are….ESTIMATES!
Forensic anthropologists give an age range to avoid excluding any possibilities in identifying unknown remains
Looking at multiple sites or multiple age indicators can narrow the range of the estimate

30. Determining Age Diaphysis makes up most of the long bone’s length
Epiphyses are found at both ends of the long bones; they function to allow growth
Good places to look for changes
Though all people are different and grow at different rates, there are similarities that make generations possible in estimating age

31. Determining Age
Epiphyses fuse to the bone during adolescence and can be examined in 4 stages:
Stage 1: nonunion with no epiphysis (no growth plate)
Stage 2: nonunion with separate epiphysis (growth plate formed but not attached)
Stage 3: partial union of the epiphysis (growth plate partially attached to bone)
Stage 4: complete union of the epiphysis (growth plate completely attached and smooth)

32. Determining Age
Stages happen at different rates in different bones and in males and females
Refer to the table on page 281 and fill in your study guide

33. Activity: Determining Age using Epiphyses
Complete the activity on pages
Work with your group to complete the activity

34. Estimating Age Based on Cranial Sutures
Additional important age indicators are the sutures located on the skull
Bones of the skull come together along special serrated and interlocking joints known as sutures, which allow for growth of the skull

35. Estimating Age Based on Cranial Sutures
Sagittal suture is located along the top of the skull, dividing right and left, and runs from the top of the skull to the middle of the back of the skull
Coronal suture runs from the temporal area on one side over the top of the skull to the other.
Lambdodial suture is located at the back of the skull

36. Estimating Age Based on Cranial Sutures
Look on page and fill in the information about cranial sutures and determining age

37. Determining Age using Os Pubis
The closing of the epiphysis is a good method to determine age in younger skeletal remains
Once epiphysis are closed, forensic anthropologists observe degenerative changes to determine age
One of the best areas to determine age in an adult is from the pubic symphysis
Undergoes a regular metamorphosis, or change, from puberty onward
Goes from regular rows to an oval surface

38. Determination of Race
There are three major anthropological racial groups
Caucasoid
People of European, Middle Eastern, and East Indian descent
Negroid
People of African, Aborigine, and Melanesian descent
Mongoloids
People of Asian, Native American, and Polynesian descent

39. Determination of Race
The major differences can be seen in skull features
Caucasiods have 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
Long bones are longer and have less curvature and a greater density
Mongoloids have a more rounded nasal aperture, a parabolic palate, rounded orbits, wide zygomatic arches, and more pointed mandibles

40. Facial Reconstruction
When unidentified remains cannot be connected to any particular missing person and traditional methods of identification have failed, facial reconstruction may be important
Uses standard tissue thickness and facial muscles to build a new face on a skull
Information from the skull and skeleton gives gender, age, and race
Artist then uses data about tissue depths to create a face
Technique is not completely accurate but has been successful in helping identify unknown persons

41. Facial Reconstruction
Steps in facial reconstruction:
Est. gender, age, and race
Glue tissue markers to landmarks directly on the skull for tissue thickness
Mark muscle insertion points
Select data set to use for the particular skull, and mount markers for the exact thickness of tissue
Mount eyes in the sockets, centered and at the proper depth
Apply clay to the skull following its contours, using the depth of the tissue markers and muscle insertion points
Make measurements to determine the nose thickness and length and the mouth thickness and width
Cover the skull with layers of skin and add details to the face

42. Facial Reconstruction
After reconstruction, additional features are added to enhance and encourage identification
Photographs are distributed to help in the identification process
Proportion is more important than accuracy
Point of facial reconstruction is to provide an image that may spark some recognition when viewed by the right person

43. Facial Reconstruction

44. The Cause of Death and Bone Anomalies
The cause of death is usually left to the pathologist to determine, but if only the skeletal remains are left, an anthropologist may be consulted.
Sometimes the cause of death is obvious, while other times a weapon mark is left with no evidence of a weapon
Investigators must be careful to note if marks happened after death
Bones left outside often have scavenger marks left by animals

45. The Cause of Death and Bone Anomalies
Bones may also show earlier injuries, joint replacements, osteoporosis, arthritis, or rickets that may help with identification
Forensic anthropology uses the knowledge and techniques of osteology, archeology, pathology, photography, art, and crime investigation to give a voice to the dead