Chapter 3: The Study of Hair Vocabulary

Class Evidence
Material that connects, but does not prove an individual or thing to a certain group. Hair is considered class evidence,
Comparison Microscope
A compound microscope that allows the side-by-side comparison of samples, such as of hair or fibers.
Cortex
The region of hair located outside of the medulla containing granules of pigment.
Cuticle
The tough outer covering of a hair composed of overlapping scales.
Hair Follicle
The actively growing root or base of a hair containing DNA and living cells.
Individual Evidence
A kind of evidence that identifies a particular person or thing.
Keratin
A type of fibrous protein that makes up the majority of the cortex of a hair.
Medulla
The central core of a hair fiber.
Melanin Granules
Bits of pigment found in the cortex of a hair.
Neutron Activation Analysis
A method of analysis that determines composition of elements in a sample.
Trace Evidence
Small but measurable amounts of physical or biological material found at a crime scene.
Follicle and Shaft
Two parts that make up a hair.
Medulla, Cortex, and Cuticle
The three layers of the hair shaft.
Cortex
The largest part of the hair shaft in humans.
Secondary transfer
the transfer of evidence such as a fiber from a source to a person, and then to another person (victim)
Late 1800s
Time period when hair was recognized as trace evidence in a criminal investigation.
The Principles and Practice of Medical Jurisprudence
Book by Alfred Swaine Taylor and Thomas Stevenson published in 1883 that contains several chapters on using hair in forensic investigations.
The Hair of Man and Animals
Book published by French forensic scientists in 1910 by Victor Balthazard and Marcelle Lambert. This text includes numerous microscopic studies of hair from most animals.
1934
The use of the comparison microscope to perform side-by-side analysis of hair collected from the crime scene and hair from a suspect or victim first occurred.
Purpose of Hair
Regulate body temperature–to keep the body warm by insulating it.
Human infant hair facts
5 million hair follicles, only two percent of which are on the head.
Microscopic characteristics of hair
pattern of medulla, pigmentation of cortex, types of scales.
Fluorescence
Characteristic of chemicals (such as hair dyes) that will absorb light and fluoresce under certain colors of light.
Arsenic, lead, drugs
Chemicals that are absorbed by the skin and hair and can be detected by toxicity screen tests.
Follicular Tag
Includes the hair follicle and root. Usually present if the hair is forcibly removed.
Six
Number of different types of hair on the human body.
Three
Number of stages of hair development.
Imbricate
Cuticle pattern of human hair.
Locard’s Exchange Principle
Whenever two objects are in contact, some transfer of material will occur.