Chapter 8 Morphology of Hair
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Introduction • Physical evidence in a variety of crimes • Not yet possible to individualize human hair to any single head or body through morphology • Still has value as physical evidence
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
8- 2
Introduction • Properly collected and submitted to the laboratory – Accompanied by adequate number of standard or reference samples – Provides strong corroborative evidence for placing individual at crime scene
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Hair Evidence
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
8- 4
Morphology of Hair • Appendage of the skin • Grows out of hair follicle • Length of a hair – From its root or bulb embedded in the follicle – Continues into shaft – Terminates at a tip end
• Shaft three layers – Cuticle – Cortex – Medulla
• Most intense examination by forensic scientist CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Figure 8–1 Cross section of skin showing hair growing out of a tubelike structure called the follicle. CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Basic Hair Structure
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Hair Facts • A hair grows from the papilla and with the exception of that point of generation is made up of dead, cornified cells • It consists of a shaft that projects above the skin, and a root that is imbedded in the skin
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
8-
Hair • Its basic components are keratin (a protein), melanin (a pigment), and trace quantities of metallic elements. • These elements are deposited in the hair during its growth and/or absorbed by the hair from an external environment. • After a period of growth, the hair remains in the follicle in a resting stage to eventually be sloughed from the body. CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Cuticle
• Resistant to chemicals • Retains structure for long periods • Scale structure covering exterior of hair – Keratinized – Flattened
• Scales always point towards the tip of the hair • Scale pattern useful in species identification CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Cuticle Patterns: Coronal
• • • • •
Crown-like scale pattern Hairs of very fine diameter Resemble a stack of paper cups Hairs of small rodents and bats Rarely in human hairs
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
8-11
Cuticle Patterns: Spinous • Petal-like scales • Triangular in shape • Protrude from the hair shaft • Proximal region of mink hairs • Fur hairs of seals, cats, and some other animals • Never in human hairs CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
8-12
Cuticle Patterns: Imbricate • Flattened-scale type • Overlapping scales with narrow margins • Commonly found in human hairs and many animal hairs
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Scanning EMs of Hair
African Hair
Malaysian Hair
Chinese Hair CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
European Hair
Indian Hair PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Scanning EMs of Hair
Rat Hair CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
Mouse Hair PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Scanning EMs of Hair Hair Follicle
Cut with Blade CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
Cut with Electric Razor PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Cortex • Main body of the hair shaft • Embedded with the pigment granules that impart hair with color – Color, shape, distribution of granules
• Points of comparison among the hairs of different individuals
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
8-17
Cortex of Hair • Found within the cuticle • Made of long thin cortical cells aligned parallel to length of hair • Within the cortex are pigment granules – made by melanocytes that give hair its color
Cortex of a damaged hair. A split end, caused when a hair shaft is pulled apart. Many split ends give hair a frizzy appearance, and cause tangles. CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Melanin Pigments’ Role In Haircolor • Black hair – densely packed melanin granules – full of eumelanin
• Brown hair – loose pattern of eumelanin-filled granules – or granules blended with eumelanin and phenomelanin – depending upon • its cool or warm tones • darkness or lightness
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Melanin Pigments’ Role In Haircolor • Blonde hair – few granules with minimal bits of eumelanin – color of blonde hair: color of the hair fiber itself
• Red hair – loosely packed granules containing phenomelanin
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
8-20
Hair Color Determined • Type of melanin present in hair cortex – Eumelanin (black pigment) – Phenomelanin (red/yellow pigment) • Number of melanin granules • Spacing of granules – close together – far apart CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Gray Hair • Pigment production slows • Natural color loses color strength • Timing varies – Contrast between the hair with no color and the hair that still has some color causes it to look gray
• Appearance: percentage of strands with no color vs. pigmented strands CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Medulla
• Cellular column running through the center of the hair – Medullary index: diameter of the medulla relative to diameter of the hair shaft • Humans less than one-third the diameter of the shaft • Animals one-half or greater
– May be continuous, interrupted, fragmented, or absent CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Medulla • Varies from individual to individual and among hairs of a given individual • Different shapes, depending the species • Humans: no medulla or fragmented – Mongoloid: continuous
• Animals: continuous or interrupted CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Medulla of Hair • Cells look like a canal running through a hair • Not all hairs have medullae • Classification – continuous ( most animals, human rare, Mongoloid race) – Interrupted (animals) – fragmented (most animals, human) – absent (human)
CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
8-25
Medulla Shape • Humans and most animals cylindrical • Other animals patterned – Cat medulla string of pearls – Deer medulla round cells occupying the entire hair shaft CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
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Medullary Index diameter of medulla diameter of the hair shaft • Medullary Index Values – Humans
