Microscopic Evidence

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Microscopic Evidence

• HAIR EVIDENCE
• FIBER ANALYSIS
• PATHOLOGY INTRO

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Microscopic Hair Analysis

• The first step in microscopic hair evaluation is
  to determine whether it is animal or human. Hair
  (and nails) is made up of a protein called
  keratin, color and trace minerals. A see-through
  outer covering called the cuticle is composed of
  overlapping scales which can be seen under the
  microscope. The pattern and shape of the scales
  help to identify the type of animal or human from
  which the hair originated. Human and animal hairs
  differ on several physical characteristics
  including

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Hair follicle in dermis under skin Hair shaft
the part we can see
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Hair Analysis

• consistent pigmentation of the hair in humans
• a regularly-defined cellular core in animals
• a club-shaped root in humans with variable shapes
  in animals
• animal coats contain several different types of
  hairs while humans do not

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Once the hair is identified as human, human
characteristics are determined which
includerace

• body region from which the hair was found
• length
• color
• whether the hair was removed forcibly from the
  body
• damage due to crushing or burning
• chemical treatment such as dyes or bleach

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Racial Variations

• Racial variations include the diameter of the
  hair shaft, density and distribution of pigment
  granules and shape of the hair in cross-section.
• Body hair is differentiated based on length,
  shaft diameter, texture and condition of the
  tips.
• Comparing all of these characteristics allows a
  forensic technician to determine if hair found at
  a crime scene matches that of a suspect or
  victim.

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Hair Shaft Layers

• CUTICLE- outside layers that has scales
• Cortex- middle layer- keratin bundles
• Medulla- Central canal running through hair
  inner layer- has 3 basic patterns

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CUTICLE

• OVERLAPPING SCALES
• KERATINIZED
• FLATTENED
• Most resistant to
• chemical decomposition
• is the cuticle
• The SCALE PATTERN is most important in
• identifying type of species.

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MEDULLA

• CENTRAL CANAL
• PATTERNS
• CONTINUOUS
• INTERRUPTED
• FRAGMENTED
• SHAPE

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MEDULLARY INDEX

• MEDULLA/HAIR SHAFT DIAMETERS
• HUMANS lt1/3

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HAIR COMPARISON
CAT
DOG
ORANGUTAN
RAT
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Hair Samples
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What is hair used for?

• Unless it is burnt, hair is extremely durable.
• It remains identifiable on bodies in an advanced
  state of decomposition or attached to a murder
  weapon long after the crime is committed.
• Hair is composed of protein substances, chiefly
  keratin, and head hair grows at an average weekly
  rate of about 2.5mm, the beard growing faster and
  body hair more slowly.
• Growth ceases at death, but as the skin shrinks
  the hair, especially the beard, becomes more
  prominent, giving rise to the murder myth that
  hair grows after death.
• The absorbent property of hair makes its
  examination important in cases of arsenic
  poisoning.
• Hair picks up the poisons from the bloodstream,
  and it is possible to work out the approximate
  strength and frequency of the dosage by analysis.

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What type of hair is CASHMERE made from?
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What type of hair is CASHMERE made from?

• GOAT
• There is a breed of goat called cashmere. Most
  raw cashmere comes from China.

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FIBER ANALYSIS

• Cotton Wool Linen Nylon Silk
  Rayon

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COTTON

• Cotton is the most widely used plant fiber.
• Cotton fibers are the hairs found on the seeds of
  the cotton plant.
• If possible, obtain a cotton boll on its stem.
• Examined under a microscope, the cotton fibers
  (use a few strands of absorbent cotton) will look
  like a flattened, irregular, twisted ribbon.
• Top three distributors
• China, India, USA

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WOOL

• Wool is the most commonly used animal fiber.
• The fiber is obtained from the soft, hairy
  covering of sheep and sometimes goats.
• Under the microscope, the wool fiber looks like a
  long cylinder with scales on it.
• The fiber is very curly and springy.
• Cloth made from wool includes cashmere, camel's
  hair, alpaca, covert cloth, flannel, gabardine,
  mohair, serge, tweed and worsted.

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LINEN

• Another common plant fiber is linen, which comes
  from the flax plant.
• This fiber is long, lustrous, and smooth. Under
  the microscope it looks like bamboo can, with
  jointed cells and split, tapered ends.
• Point out that linen is often used to make
  handkerchiefs, tablecloths, napkins, summer
  clothing, pants and blouses.

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SILK

• Silk, another common animal fiber, was once quite
  popular, but has been replaced to a great extent
  by such synthetic fibers as Nylon, Orlon, and
  Dacron.
• Silk is made by the mulberry silk worm when
  spinning its cocoon.
• Under the microscope the silk fiber appears as a
  thin, long, smooth and lustrous cylinder.
• Cloths made from silk include brocade,
  brocatelle, chiffon, crepe, velvet, satin,
  taffeta, tulle, and falle.
• Silkworms (China) spin silk like spiders spin a
  web!

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RAYON

• Rayon is one of the first successful artificial
  fibers. It is made from cellulose.
• When manufactured, the rayon fibers resemble
  silk.
• Under the microscope, the rayon fiber looks like
  a smooth, lustrous cylinder.
• Rayon can be made into cloth that is hard to
  distinguish from silk, cotton, linen, or wool.
• Celanese is one form of rayon.

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ASBESTOS

• Asbestos is the name given to a group of minerals
  that occur naturally as masses of strong,
  flexible fibers that can be separated into thin
  threads and woven to make asbestos cloth.
• These fibers are not affected by heat or
  chemicals and do not conduct electricity.
• Asbestos cloth was used in fireproof theater
  curtains and protective suits for use by fire
  fighters.
• It was also used as a building material, brake
  pads and a range of other products.

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ASBESTOS

• It is now know that the fibers of asbestos are a
  dangerous irritant.
• Even exposure to small amounts of asbestos dust
  can lead to a range of illnesses such as
  asbestosis, a serious lung inflammation caused by
  asbestos exposure, and Mesothelioma a cancer of
  the chest and abdomen.
• Although asbestos products are rarely made these
  days, they can still be found, particularly in
  old buildings.

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Synthetic Fibers

• Today there is a wide variety of synthetic
  fibers all have trade names such as Nylon,
  Orlon, Dacron, Vinyon, Aralac, Acrilan, Velon,
  Dynel, Banlon and Lycra. Like rayon, these fibres
  resemble silk, and under the microscope look like
  smooth, lustrous cylinders.
• Synthetic fibers are easily identified because of
  their uniform thickness (the thickness of natural
  fibers varies).
• Synthetic fibers area made into fabrics that have
  special properties..

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Synthetic Fibers

• Glass and asbestos can also be spun into thread
  and woven into fabrics.
• Glass fibers are made by stretching melted glass
  into fine filaments, which are spun into thread
  for weaving into cloth.
• Lightweight glass fibers are used to make long
  lasting windows curtains, drapes, and lamp
  shades.
• Heavier glass fabrics are used to make fireproof
  theater and school curtains.

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FORENSIC PATHOLOGY

• A branch of pathology concerned with determining
  cause of death by observing tissue, organs,
  bodily fluids and whole bodies.

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Sperm Cells

• Sperm cells move by means of flagella

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Terms to understand

• CANCER- the uncontrolled growth of abnormal cells
  in the body.
• Carcinoma cancer
• Malignant tumor cancer
• Benign tumor not cancerous (moles/ fibroids)
• Limited growth (does not spread)
• Does not affect surrounding area
• Does not metastasize
• Some types of benign tumors can cause negative
  health effects or can turn into malignant tumors
• Metastasis-the spread of a disease from one organ
  or part to another non-adjacent organ or part.

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Example of MetastasisPrimary cancer in pancreas
which has caused secondary liver tumors
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CELLS
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Normal cells are uniform and arranged in tissues
in an orderly manner. When you poke and prod
normal tissue, its soft.
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Paraganglioma shows polygonal chief cells
enclosed by fibrous elongated cellsOR Head/Neck
Cancer Cells
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Tumor cells have large, irregular nuclei, a small
cytoplasm and large variations in size and shape.
The cells are arranged in a disorganized fashion.
Ex Brain Tumor
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A renal cell carcinoma stained slide
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Lung DiseasePathology of lung showing
centrilobular emphysema characteristic of
smoking. Close-up of fixed, cut surface shows
multiple cavities (aveoli) lined by heavy black
carbon deposits.
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Slides to examine
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Sketching the Evidence