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Hair …and more hair. Hair as Evidence Hair …and more hair. Hair as Evidence

Hair …and more hair. Hair as Evidence - PowerPoint Presentation

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Uploaded On 2018-10-21

Hair …and more hair. Hair as Evidence - PPT Presentation

Can only compare head hair to head hair or pubic hair to another pubic hair Control hairs from suspect 50 full length head hairs minimum of 24 pubic hairs HAIR is useful as forensic evidence because its protein polymers are ID: 692557

hairs hair index growth hair hairs growth index human average medulla anagen cortex animals 000 phase patterns root diameter

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Slide1

HairSlide2

…and more hair.Slide3

Hair as EvidenceCan only compare head hair to head hairor pubic hair to another pubic hair Control hairs from suspect: 50 full length head hairs

minimum of 24 pubic hairsSlide4

HAIR is useful as forensic evidence because its protein polymers are…Resistant to decomposition and maintains its structure.Slide5

The average human body has about 5 million hairs!Slide6

Some HAIRY facts…The average number of Brown/Black scalp hairs: 100,000! Slide7

On the average, the human scalp has100,000 hair follicles. You are born with as many hair follicles as you are ever going to have!Slide8

Blondes have 120,000Slide9

Redheads have at least80,000Slide10

Average daily # of hairs shed: 50 - 100Slide11

Fastest Growth..Between 15 and 30 years of ageSlide12

Slow Growth..Slide13

Average Scalp hair growth… 0.35 mm/day or about 1 cm/monthSlide14

Hair grows faster … In summerSlide15

Month of greatest hair shed in Northern Temperate zone: NOVEMBERSlide16

Hair Morphology (structure)Slide17

Structure from which hair growsLies below epidermisCan differentiateBetween species

Sticks out of skinSlide18
Slide19

The organ that hair grows out ofSlide20

Cross Section of hairThe Hair shaft is made up of….1. The CUTICLE is the outside covering Slide21

a. SCALES cover the cuticleThe cuticle protects the cortexSlide22

In Humans Scale patterns are not useful forensically because the scale patterns in humans are the sameSlide23

In animals, a variety of scale patterns are found

bat

mink

deerSlide24

Scales always point toward the tip of hair(1) mosaicSlide25

(2) pectinateSlide26

(3) imbricateSlide27

(4) petalSlide28

(5) Diamond petalSlide29

(6) chevronSlide30

2. Cortex – gives hair its shape The bulk of each hair’s mass is contained in the cortex. Slide31

The CORTEX… contains the various proteins and bonds which determine the curliness or straightness of the hair. Slide32

a. melaninPigment granules that give hair its colorSlide33

b. Cortical fusiAir spacesUsually found near the rootBut can be foundThroughout the Hair shaftSlide34

3. Medulla – “central canal”-Formed by cells running through hair-Amorphous in appearanceSlide35

Medullary Index = diameter of medulla diameter of hair

The medulla is

approximately.005 mmIn width

This hair is

.

030 mm

in

diameter

The Medullary Index =

.

005

mm

.

030

mm

= 1/6Slide36

Degree of variations in medullasVary from one individual to anotherAnd even between hairs of one person Human hair Medulla index < 1/3 in other animals: ½ or greaterSlide37

a. Types of medullas (Human)continuous

fragmented

absent

Interrupted

or intermittentSlide38

b. Patterns (other animals)Uniserial

multiserialSlide39

(3) Vacuolated Mountain lionSlide40

(4) latticeSlide41

(5) Amorphous – without a clear formSlide42

Hair as Evidence Determine…

1. Human or animal?

In Humans:

Medullary Index

<

1/3

In Other Animals:

Medullary Index

≥ 1/2

Slide43

2. Race (ethnicity)Negroid hairsNegroid or African origin hairs are usually curly with a flattened cross

section and appear to be curly, wavy, or coiled. Slide44

Caucasian hairs Caucasoid or Caucasian origin hairs are normally fine to medium coarseness, oval cross-section, straight or wavy in appearance, and colors range from blonde to brown to black. Slide45

Mongoloid or Asian hairs Mongoloid or Asian origin hairs are normally coarse, straight, with a wider diameter than hairs of the Caucasoid and Negroid hairs. The outer layer of the hair is usually much thicker than that of the other racial groups. Slide46

3. Origin –from which part of bodyScalp hairs - all about the same diameterBeard hairs - coarse, blunt tips

Pubic hairs - short, curlySlide47

4. Manner in which hair was removedForcibly removed hair will include the root tipSlide48

Follicular Tag contains tissue surrounding hair shaft Contains DNA!!Slide49

5. Treated Haira. rootsSlide50

b. Dye present in cuticle or cortexSlide51

c. Bleached hair Removes color, yellow tintSlide52

6. Drug Testing Hair testing is considered accurate and can go back as far as 90 days Slide53

Hair Comparison

1. Color, straight

vs

wavy

vs curly, etc.Slide54

2. Presence or absence.. of medullaSlide55

3. Pigment Granules In the cortexSlide56

4. Dyed or bleached?Slide57

5. Abnormalities Vitamin deficiency fungus nits (lice)

Or diseasesSlide58

Hair GrowthFunction of the root – nourishment for hair growthSlide59

A. TERMINOLOGY Phases of growth 1. anagen - the root is attached to the follicle GROWTH PHASE lasts 2-6 yrs 90%of hair is in anagen Slide60

Anagen hair rootsSlide61

2. Catagen The root bulb shrinksThe growth rate decreasesLasts 2-3 weeksSlide62

Catagen –TRANSITION stageSlide63

3. TelogenRESTING phase2-6 monthsSlide64

Telogen plase Is also called the SHEDDING phaseSlide65

Hair shed rate 50 – 100 hairs per daySlide66

Each Hair is in Growth phase (Anagen) For 2 – 5 yearsSlide67

% Hair in Growth Phase (Anagen) 85% - 90%