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it may result from natural exposure to the sun. A hair that has been bleached
from exposure to sun is often referred to as a solar-bleached hair. A bleached
hair may be recognized by the presence of a demarcation line between the
treated portion and the naturally pigmented newly grown portion. The
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bleached portion may contain no pigment granules, or it may contain sig-
nificantly fewer pigment granules than the natural portion. The demarcation
line of solar-bleached hair typically is not as distinct as the demarcation line
of artificially bleached hair. Repeated dyeing and bleaching of a hair may
result in several lines of demarcation that might render a hair as being
unusual, resulting in a hair comparison that might have greater significance.
Permanent waved hairs sometimes may have buckles or bends in the hair
shaft due to the use of perm curlers. These buckles may present themselves
at roughly even intervals along the hair shaft due to the manner in which
the hair is wrapped around the curler. Artificially straightened hairs some-
times may be recognized by the simple observation that a straight hair has
a cross-sectional shape (e.g., oval, flat) that is more consistent with curly hair.
3.22 Hair Diseases and Disorders
Table 3.1 lists some hair diseases and hair disorders found in human hair.
Hair diseases and disorders are very rare, and their presence in both a ques-
tioned hair and a known hair sample in forensic examinations may
strengthen considerably the opinion that the questioned hair could have
come from the same individual as the known specimen. The hair diseases
listed in Table 3.1 are Trichorrhexis Nodosa, Trichorrhexis Invaginata, Tri-
choschisis, Pili Annulati, Monilethrix, Pili Torti, Trichonodosis, Cartilage
Hair Hypoplasia, and Other. Discussion of these diseases and disorders is
deferred to Chapter 5 so that the reader may refer to Figure 5.21.1, which
illustrates them.
3.23 Miscellaneous Characteristics
Miscellaneous characteristics are those characteristics that do not fit into any
of the other categories listed in the various tables presented in this atlas.
These characteristics are listed in Table 3.1. Miscellaneous characteristics
include Double Medulla, Streaky Medulla, Gapping Pigment, Debris Present,
Trailing Ovoid Bodies, and Other. Photographic archetypes illustrating
examples of those miscellaneous characteristics are presented in Chapter 5.
The variate Other may include any other notable characteristic not discussed
here. Any unusual characteristics should be described fully in the notes and
augmented with photographs in the examiner s or researcher s case file.
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3.24 Insect, Arachnid, and Fungal Presence and Damage
The insect, arachnid, and fungal presence and damage listed in Table 3.1
includes lice/louse eggs, insect/arachnid damage, fungal damage, and other.
The presence of louse eggs is easily diagnosed from the characteristic appear-
ance of the egg attached to the hair shaft. Insect or arachnid damage can
usually be diagnosed from the patterned appearance of the damage, while
fungal damage has a more amorphous aspect. The variate Other refers to
biological damage to hair that cannot be categorized easily as insect/arachnid
or fungal damage. Photographic examples of each variate are presented in
Chapter 5.
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Human Hair Cross-Section
Characteristic Variates
4
Table 4.1 lists the following microscopic characteristic variates as seen in
cross-section mounts of the hair: cross-section shape, cuticle thickness, pig-
ment density, pigment size, pigment distribution, and cortical texture. This
chapter provides a brief description of each cross-section characteristic. Pho-
tographic archetypes that illustrate cross-section shape and cross-section
pigment distribution are presented in Chapter 5. For a discussion on cross-
section techniques, see Fong and Inami.17
It should be noted that the cross-section view of most characteristics
does not represent additional characteristics for the purpose of hair com-
parison but rather adds a different view of the same characteristic. The cross-
section may, however, resolve a question regarding the precise diagnosis of
a characteristic that is difficult to diagnose in the longitudinal mount. The
cross-section may assist in resolving questions regarding the pigment distri-
bution about the medulla, the precise cross-section shape, or the cross-
section cortical texture. Cuticle thickness, pigment density, and pigment size
usually can be easily diagnosed in the longitudinal view by an experienced
examiner.
4.1 Shaft Cross-Section Shape
The hair shaft cross-section shape usually can be diagnosed by an experienced
hair examiner in a longitudinal mount. However, in some cases, the cross-
section view allows the examiner to be more precise and accurate in the
assessment of cross-section shape, since the cross-section gives a direct view
of the shape. The cross-section shape variates are listed as Round, Oval,
Triangular, Flat, Kidney, and Shouldered. The triangular shape is seen often
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Table 4.1 Human Hair Cross-Section Characteristicsa
0.1 Shape
BB01 Round BB02 Oval BB03 Triangular
BB04 Flat BB05 Kidney BB06 Shouldere
d
02. Cuticle Thickness
CC01 Thin CC02 Thick CC03 Varies
03. Pigment Density
DD01 Light DD02 Medium DD03 Heavy
DD04 Opaque
04. Pigment Granule Size
EE01 Fine EE02 Coarse
05. Pigment Distribution
FF01 Uniform FF02 Peripheral
FF03 Central FF04 One-sided
06. Cortical Texture
GG01 Absent GG02 Present GG03 Obscured
a
Table 4.1 adapted from Table 3, Ogle, R. R., Jr., Individualization of human
hair: the role of the hair atlas, Microscope, 46(1), 20, 1998. With permission.
in beard hairs and rarely in scalp hairs. The cross-section shape of the tran-
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