Name ______________________________________________________ Date ________________
Hair & Fiber Review
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What is the definition of “Trace Evidence”? any small piece of material, naturally occurring or man-made that
can link a victim, a suspect or an object to a crime scene.
Describe hair as evidence. How common is it? Does it change with time? Is it considered class or individual
evidence? Hair is very common, abundant. It does not change with time and is considered class evidence –
even two hairs from the same head can look different.
What type of crime is usually associated with hair evidence? Violent, sexual crimes.
Describe the type of information that can be obtained from analyzing a single hair:
a. If the source is human or animal
b. Race (sometimes)
c. Origin of the location on the source’s body
d. Whether the hair was forcibly removed
e. If the hair has been treated with chemicals
f. If drugs have been ingested
The outer layer of the hair shaft is the cuticle.
The middle layer of the hair shaft is the cortex.
The inner layer of the hair shaft is the medulla.
The melanin are pigment granules that give hair its color.
The cortical fusi are pockets of air found in the cortex.
Label the following:
A = a pigment in the cortex, B = medulla, C = cortex, D = an air sac in the medulla, E =
cuticle
11. Approximately how fast does hair grow? About 0.5 mm per day or 1.0 cm per month
12. Label the picture to the right:
a. A = follicle, B = shaft, C = root
13. List and describe the three phases of hair growth:
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Anagen - hair that is growing up to 6 years; root has a flame shaped appearance and may have a follicular tag
from which DNA may be obtained
2. Catagen - hair at rest for 2-3 weeks; has elongated appearance
3. Telogen - hair growth is ended; has club shaped appearance
14. Name the cuticle scale pattern found on a hair of each of the following:
a. Human - imbricate
b. Rabbit - __chevron__
c. Cat – mosaic
d. Rat - Pectinate
e. Dog (coarse) – Diamond Petal
f. Dog (fine) – petal
g. Bat - Coronal
h. Mink - Spinal
15. Label the following scale patterns:
A = mosaic, B = chevron, C = diamond petal, D = pectinate,
E = imbricate
F = Petal
16. The ________________________ is the central canal running through the hair core that is not always present.
17. List and draw the different types of medullae (plural for medulla)
a. Continuous - _______________________________________
b. Intermittent or interrupted ____________ ____________ __________
c. Fragmented _______
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d. Absent--not present
18. Identify the hair medulla patterns below and give an example of an animal whose hair exhibits the same
morphological features:
A = uniserial – cat,
C = vacuolated – dog,
B = multiserial – rabbit,
D = lattice - deer
19. The medullary index measures the diameter of the medulla relative to the diameter of the hair shaft.
20. Medullary Index for human hair is generally less than 1/3. For animal hair, it is usually greater than _1/2_.
21. How does the root of a hair that was forcibly removed differ in shape from the root of a hair that has fallen out?
A follicular tag (tissue) will be attached to the forcibly removed hair, while the root of a hair that has fallen
out will have a club shape.
22. A _follicular tag_ is a rich source for nuclear DNA, while the hair shaft may possibly contain mitochondrial DNA.
23. Tips of Hair – describe the tip of the hair for the following scenarios:
a. Recently cut - Blunt
b. Cut and allowed to grow - Rounded
c. Show the presence of a flame – Blackened or frayed
d. Broken – Ends will be irregular
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24. Hair Shape – identify the type of hair and race associated with each shape.
Crescent – Kinky - African
Round – straight - ASIAN
Oval – Curly/Wavy - Caucasian
25. List the three methods of hair collection:
a.
Visual
b.
Tape - Lift
c.
Vacuuming
26. Which of the above method is the least effective? vacumming
27. Questioned hairs must be accompanied by an adequate number of control samples. These samples are taken
from:
a. The victim
b.
Possible suspects
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Others who may have deposited hair at the scene
28. A control sample contains 50 full-length hairs from all areas of scalp and 24 full-length pubic hairs.
29. Fibers are classified as natural or man-made(synthetic).
30. Natural fibers can come from the following sources:
a. Animal -Protein
b. Plants-Vegetable
c. Excrement
d. Mineral
31. Man-made fibers are either synthetic or regenerated.
32. Cotton fibers are by far the most commonly used plant fibers in textile production.
33. The most common animal fiber used in textile production is wool.
34. The most commonly used regenerated fiber is rayon.
35. Rayon was the first regenerated fiber created while nylon was the first synthetic fiber created.
36. List the following as either natural/plant, natural/animal, man-made/regenerated, man-made/synthetic:
cotton
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Natural/animal wool
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man-made/regenerated :rayon
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natural/plant hemp
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man-made/synthetic polyester
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natural/animal fur
Man-made/regenerated acetate
natural/animal mink
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natural/animal _ silk
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man-made/synthetic spandex
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natural/animal cashmere
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man-made/synthetic nylon
natural/animal mohair