Chapter 7 - Anatomical Evidence Flashcards
Trace evidence
- Deals with the minute transfers of materials that cannot be seen with the unaided eye.
- Include fingerprints, hair, fiber, glass, soil,
explosives. - Trying to see if the evidence’s origin/method of use can be identified.
Latent prints
Prints not visible to the naked eye.
Addition Reaction (polymers)
- Chemical reaction where the net result is to add monomers together without the loss of any part of the monomer.
AFIS
- Automated Fingerprint Identification System
- Large database of fingerprints
Anagen Phase
Phase of active growth for hair formation
Apocrine Gland
The scent glands
3 patterns of the fingerprint ID system
- Loop
- Arch
- Whorl
Arch pattern
- Found in 5% of all fingerprints
- Ridges beginning at one side of the fingerprint and running completely to the other side of the
fingerprint without a backwards turn.
Authentication/Verification
Compares biometric info from one person with either just one reference or from a very small number of possibilities.
IDENT
- Automated Biometric Identification System
- Used to link a person with their biographic info
- Criminal record, personal ID, and travel restrictions, for security and law enforcement work
Bifurcation
- Minutial feature
- Point where a single ridge splits into 2 ridges
Biometrics
- Automated recognition of individuals by means of unique physical characteristics.
- Used for security.
Catagen Phase
- Transitional phase
- Hair follicle detaches from blood supply which stops supply of nutrients required for growth.
- Lasts several weeks
Hair Growth Cycle
- Anagen phase
- Catagen phase
- Telogen phase
Catalysts
A substance that increases the rate of a reaction without being consumed
Cheiloscopy
The study of lip groove patterns
Cellulose
- A complex sugar or polysaccharide molecule
- Found in many plant-based fibers.
Condensation reactions
- Common way to form a polymer from monomers.
- 2+ molecules combine to form a larger molecule while losing a small molecule (H2O).
Core
- Important print feature
- Where a loop pattern reaches its farthest point (near edge of print) towards the middle of the print and begins to turn backwards.
Hair fibers are made-up of 3 components
- The cuticle
- The cortex
- The medulla
Cuticle
- Outermost layer of a hair shaft.
- Looks like shingles on a roof or scales on a snake’s skin.
- Protects the hair by forming a waterproof
layer that coats the entire shaft. - 3 types of patterns: coronal, spinous,
imbricate
Cortex
- Underneath the cuticle layer
- Takes-up most of the inside of the hair follicle.
- Provides strength, elasticity, moisture, color, texture
Delta
- Important print feature
- The point of ridge divergence where the upward and downward ridges meet the looping ridges
- Looks like a small triangle
3 layers of the skin
- Epidermis
- Dermis
- Hypodermis
Dermis
- Middle layer of the skin
- Contains nerve endings, oil glands, sweat glands, and hair follicles.
Eccrine glands
The sweat glands
Ectoderm
- Outermost germ layer developed during embryonic growth.
- Gives rise to our epidermis, hair, eyes, nervous system.
Elastomers
- Synthetic polymers with special elastic properties
- Ex: spandex
Ending ridge point
- Point where a ridge ends abruptly
Epidermis
- The outermost layer of our skin
- Contains cells that produce pigment and protect the immune system.
- Ranges in thickness (very thin on our eyelids and thick on the palms of our hands/soles of our feet).
Eumelanin
The dark pigment that colors black and brown hair
Fibers
Small filaments that are long and thin with lengths greater than widths
Fingernails
- Hard protective structures at the ends of fingers
- Composed of keratin
- Considered to be an appendage (addition) of the skin
Fingerprint
- The impression made on a surface by the unique set of ridges found on a person’s fingers
- Used for the individual ID of an individual
Fingerprint lifting
- Method of preserving fingerprints
- Cellophane tape is placed over the print and then rubbed
- The tape holds the pattern of the fingerprint when lifted
Friction ridges
- Skin present on fingers, palms, and soles of feet.
- Ridges and furrows are unique and aid in gripping (increased surface area)
Fuming Fingerprint Visualization
- Chemical method for the detection of latent fingermarks on non-porous surfaces.
- Using cyanoacrylate
Furrows
Lower valleys next to/between the ridges of fingerprints
Hair
- Composed mostly of keratin
- Grows from a follicle in the skin
- Derivative of the skin’s epidermis
- Functions mainly to regulate body temp of an organism by trapping/releasing warm air near the skin’s surface
IAFIS
- Integrated Automated Fingerprint
Identification System - Revised automated fingerprint database
Identification
Using biometric info to ID an unknown person from a large pool of possibilities.
Impression prints
Fingerprints left in a soft, pliable surface, such as clay, putty, or soil
Integumentary System
- Forms the outer boundary of our bodies
- Includes our hair and nails
Iodine
- Element that reacts with the oils left behind by fingers
- Forms a transient, observable, brown color where the finger oils were deposited
Keratin
- Tough, durable protein composed of long chains of amino acids and found as a structural component of hair, nails, horns, claws
Loop pattern
Fingerprint pattern that has ridge lines that enter on one side of the fingerprint, run towards the middle of the print, then curve backwards to exit on the same side
Medulla
- Innermost component of hair
- Has spongy cells and form a canal-like structure in the center of the shaft
- Contains melanin and other proteins
- Some finer hair follicles don’t have a medulla
Medullary Index (MI)
- Ratio of the medulla’s width to the diameter of the hair
Melanin
- Pigment that gives color to skin and eyes
- Protects it from damage by UV light.
Minutiae
The fine details of fingerprint patterns
Monomers
The building blocks that make up polymers
Natural fibers
- Fibers that come from naturally occurring sources
- Plants, animals, wood, spider’s silk, etc
Ninhydrin
- Reacts with the amino acids found in a fingerprint
- Forms a purple/blue-colored pattern of the fingerprint when heated
Palmprint
Pattern left by the flexion creases and ridges found in the palm of the hand/sole of the foot
Flexion creases
Places where the skin flexes or folds to cause breaks in the observed ridge patterns
Pheomelanin
Pigment coloration chemical found in red hair
Pinnascopy
Patterns of the ears used for individual identification
Polymers
Chains of monomers strung together
Principle of Persistency
- A biological feature (once formed) remains unchanged throughout our lives
- May last beyond death into the stages of decay
Regenerated Fibers
Fibers made by processing naturally occurring materials into fibers
Ridge count
The number of ridges between two features in a fingerprint pattern
Sebaceous Glands
- Glands in the skin that produce sebum
- Sebum: sticky, oily substance the body produces to keep the skin moisturized
Synthetic Fibers
Fibers prepared from chemical feedstocks and formed through reactions that create long chain molecules
Telogen Phase
- The resting period
- The detached club root has completely formed
Thermoplastic
Synthetic fibers that melt or soften easily at low temps
Vellus Hair
The fine short hairs that covers the majority of the human body
Visible Fingerprints
Fingerprints able to be observed by the naked eye
Whorl Pattern
- Fingerprint pattern where the ridges complete at least one 360° circuit
- Does not always form a circle pattern
