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48 Cards in this Set
- Front
- Back
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Fundamental principles of Fingerprints |
Doesn't change; individual characteristic; general ridge patterns that permit them to be systematically classified |
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Delta |
The ridge point at or nearest the type line divergence and located at or directly in front of the point of divergence |
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Core |
Approximate center of the pattern |
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3 classes of Fingerprints |
Loops, Whorls, and Arches |
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Loops |
Must have one or more ridges entering from one side of the print, recurving, and exiting from the same side |
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Ulnar Loop |
loop opening toward the little finger |
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Radial Loop |
Loop opening toward the thumb |
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Type Lines |
Pattern area surrounded by two diverging ridges |
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What must all loops have? |
One delta |
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Whorls |
Divided into 4 Groups: Plain, Central Pocket loop, double loop, and accidental |
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What must all whorls have? |
type lines and at least two deltas |
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Plain and central pocket have what? |
Atleast one ridge that makes a complete circuit. (may be in the form of a spiral, oval, or any variant |
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Plain Whorl |
A line drawn b/w two deltas touches any one of the spiral ridges |
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Central Loop Pocket |
When no line touches a ridge |
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Double Loop |
Two loops combined into one fingerprint |
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Arches |
Least common |
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Two types of Arches |
Plain and dented |
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Plain Arch |
(Simplest) formed by ridges entering from one side of the print and exiting on the opposite side |
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Tented Arch |
Sharp spike or ridges meet at an angle that is less than 90 degrees |
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What Don't Arches have? |
Typelines, deltas, or cores |
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Latent Prints |
Any fingerprint discovered at a crime scene (invisible) |
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Visible Prints |
Made by fingers touching a surface after the ridges have been in contact w/ a colored material such as blood, paint, grease |
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Plastic Prints |
Ridge impressions left on a soft material (putty, wax, soap, or dust) |
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Hard-Surfaces |
glass, mirror, tile, and painted wood; treat with powder or superglue |
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Soft and Porous |
Paper, cardboard, cloth; treat with chemicals |
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RUVIS |
can locate prints on most nonabsorbent surfaces w/o the aid of chemical or powder treatments |
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Fingerprint Powder |
When applied lightly to a nonabsorbent surface w/ a camel's hair or fiberglass brush, adheres to perspiration residues and/or deposits of body oils left on the surface |
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Gray Powder |
Used on dark colored surfaces and mirrors and metal surfaces b/c these photograph as black |
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Magnetic-Sensitive Powder |
Comes in black and gray and is especially useful on such items as finished leather and rough plastics, where the texture tends to hold particles of ordinary powder |
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Florescent Powders |
Color of the surface cannot obscure the print when used under a uv light |
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Iodine Fuming |
Material is placed in a closed chamber w/ iodine crystals. As the crystals are heated, the vapors fill the chamber |
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Hai Follicle |
an organ in which hair grows out of |
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What makes up the hair shaft? |
Cuticle, cortex, and medulla |
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Cuticle |
Outside covering of the hair; formed by overlapping scales that always point toward the tip end of each hair; "shingles" |
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3 Patterns of the Cuticle |
cornal, spinous, imbricate |
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Cortex |
contained within the protective layer of the cuticle; made up of spindle-shaped cortical cells aligned in a regular array, parrallel to the length of the hair; embedded w/ the pigment granules that give hair its color |
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What are the important points of comparison among the hairs of different individuals? |
color, shape, and distribution of pigment granules |
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Medulla |
A collection of cells that looks like a central canal running through a hair; occupies more than half of the hair's diameter |
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Medullary Index |
Measures the diameter of the medulla relative to the diameter of the hair shaft and is normally expressed as a fraction |
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Anagen Phase |
can last up to 6 years; root bulb has a flame-shaped appearance; when pulled from root, some hairs have a follicular tag |
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Catagen Phase |
hair grows at a decreasing rate; can last from 2-3 weeks; root takes on an elongated appearance |
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Telogen Phase |
growth ends; root has a club-shaped appearance; over 2-6 months; hair shedding |
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Natural Fibers |
Animal or plants |
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What fibers do most crime labs encounter? |
Animal |
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What is the most prevalent plant fiber? |
Cotton |
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An example of animal fibers |
wool, cashmere |
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Manufactured Fibers |
natural or synthetic polymers; made by forcing the polymeric material through the holes of a spinneret |
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Examples of manufactured fibers |
Spandex, Acrylic, Nylon, Polyester |
