1. Chapter 3 The Study of Hair By the end of this chapter you will be able to:
Identify the various parts of a hair
Describe variations in the structure of the medulla, cortex, and cuticle
Distinguish between human and nonhuman hair
Determine if two examples of hair are from the same person
Explain how hair can be used in a forensic investigation
Calculate the medullary index for a hair
Forensic Science: Fundamentals & Investigations, Chapter 3

2. History of Hair Analysis
1883: Alfred Swaine Taylor and Thomas Stevenson covered ______ in a forensic science text
1910: Victor Balthazard and Marcelle Lambert published a comprehensive study of hair (the hair of man and ______)
1934: Dr. Sydney Smith, analyzed hairs side by side from a crime scene
Today: chemical tests, neutron activation analysis, and DNA analysis
Forensic Science: Fundamentals & Investigations, Chapter 3

3. The Function of Hair
All mammals have hair. When humans are born, they have about ___ million hair follicles, only 2 % of which are on the head.
Regulates body temperature
Decreases friction
Protects against _______
Forensic Science: Fundamentals & Investigations, Chapter 3

4. The Structure of Hair A hair consists of two parts: ______ & shaft
A follicle is embedded in the skin which produces the hair shaft
The hair shaft is made up of ______ layers
the inner medulla
the cortex
the outer cuticle
Forensic Science: Fundamentals & Investigations, Chapter 3

5. The Structure of Hair http://www.youtube.com/watch?v=xqZ16iNPaac
Forensic Science: Fundamentals & Investigations, Chapter 3

6. Cuticle Cuticle: transparent outer layer of the hair shaft.
Made of over-lapping ______ that protect the inner layers
When examining a hair under a microscope, noticing the direction of the scales point shows you ______ and older ends of the hair.
This info can be used when investigating hair for the presence of toxins, _____, or metals at specific points in time.
Forensic Science: Fundamentals & Investigations, Chapter 3

7. Cortex Cortex: Thickest layer – largest part of the hair shaft.
Contains most of the ______- which gives hair its color (melanin)
Distribution of pigment varies
Usually denser nearer the cuticle
Forensic Science: Fundamentals & Investigations, Chapter 3

8. Medulla The center of the hair is called the medulla
In some people the medulla is _____, in others its fragmented or segmented , and in others its continuous or even doubled.
Forensic Science: Fundamentals & Investigations, Chapter 3

9. Types of Hair
Buckled Blunt Double Medulla
Hair can vary in shape, length, diameter, texture, and color.
Hairs also vary from body ______ – usually 50 hairs are taken from a suspects head and 25 are taken from the pubic region
Forensic Science: Fundamentals & Investigations, Chapter 3

10. Types of Hair Human hair varies on the body Head Eyebrows Lashes
Mustache
Beard
Underarms
Body hair
Pubic
Forensic Science: Fundamentals & Investigations, Chapter 3

11. Racial Differences
Broad, racial groups do exhibit some shared physical _______
But NOT applicable to all individuals in these groups
Therefore,
Individual hairs _______ be assigned to any of these groups
Forensic Science: Fundamentals & Investigations, Chapter 3

12. The Life Cycle of Hair Hair proceeds through 3 stages as it develops:
Anagen stage:
Lasts approximately _____days, hair actively grows
cells around the follicle rapidly divide and deposit materials in the hair
Catagen stage:
hair grows and _______ (like turning grey)
Telogen stage:
follicle becomes _______ – hairs are easily lost.
Forensic Science: Fundamentals & Investigations, Chapter 3

13. Forensic Science: Fundamentals & Investigations, Chapter 3

14. What does your hair say about you?
Forensic Science: Fundamentals & Investigations, Chapter 3

15. Animal Hair and Human Hair
Pigmentation:
animal hair is _______ toward the medulla
human hair tends to be denser toward the cuticle
Banded Color Patterns:
possible in animals--- not in humans
Medulla: much _______ in animals
Forensic Science: Fundamentals & Investigations, Chapter 3

16. Medulla Index— Animals vs. Humans
Forensic Science: Fundamentals & Investigations, Chapter 3

17. Animal Hair and Human Hair
Spinous Coronal Imbricate
Animals: cuticle scales resemble petals (spinous) or a stack of crowns (coronal)
Humans: commonly flattened and narrow (imbricate)
Forensic Science: Fundamentals & Investigations, Chapter 3

18. Animal hair as evidence
Forensic Science: Fundamentals & Investigations, Chapter 3

19. Using Hair in an Investigation
Macroscopic investigations indicate
length
color
curliness
______ contrast microscopy shows
presence of dye or other treatments
Electron microscopes yield yet ______ detail
Forensic Science: Fundamentals & Investigations, Chapter 3

20. Testing for Substances in the Hair Shaft
Chemical tests
presence of various ________
Examining a hair shaft
timeline for exposure to toxins
Neutron Activation Analysis (NAA)
________ of substances
Forensic Science: Fundamentals & Investigations, Chapter 3

21. Testing the Hair Follicle
Microscopic assessment
Cost effective and _____
Blood test
Determine blood ______
DNA analysis
Identification with a high degree of confidence
Forensic Science: Fundamentals & Investigations, Chapter 3

22. Microscopic Assessment
Preparation
Forensic Science: Fundamentals & Investigations, Chapter 3

23. Hair evidence on trial (Casey Anthony trial)
Forensic Science: Fundamentals & Investigations, Chapter 3