Microscopic Evidence• HAIR EVIDENCE• FIBER ANALYSIS• PATHOLOGY INTRO

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

Hair follicle= in dermis under skinHair shaft= the part we can see

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

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

race • 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

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.

Hair Shaft Layers

1. CUTICLE- outside layers that has scales2. Cortex- middle layer- keratin bundles3. Medulla- Central canal running through hair=

inner layer- has 3 basic patterns

CUTICLEOVERLAPPING SCALES– KERATINIZED– FLATTENED

Most resistant to chemical decompositionis the cuticle

The SCALE PATTERN is most important in identifying type of species.

MEDULLA

• CENTRAL CANAL• PATTERNS

– CONTINUOUS– INTERRUPTED– FRAGMENTED

• SHAPE

MEDULLARY INDEX• MEDULLA/HAIR SHAFT DIAMETERS• HUMANS <1/3

HAIR COMPARISONCAT

DOG

ORANGUTAN

RAT

Hair Samples

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.

What type of hair is CASHMERE made from?

What type of hair is CASHMERE made from?

GOATThere is a breed of goat called cashmere. Most raw cashmere comes from China.

FIBER ANALYSIS

Cotton Wool Linen Nylon Silk Rayon

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

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.

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.

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!

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.

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.

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.

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..

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.

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

Sperm Cells

Sperm cells move by means of flagella

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.

Example of MetastasisPrimary cancer in pancreas which has caused

secondary liver tumors

CELLS:

Normal cells are uniform and arranged in tissues in an orderly manner. When you poke and prod normal

tissue, it’s soft.

Paraganglioma shows polygonal chief cells enclosed by fibrous elongated cells

OR Head/Neck Cancer Cells

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

A renal cell carcinoma stained slide

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.

Slides to examine

Sketching the Evidence: