fingerprints Flashcards
chapter 2
what is dactylography or dactyloscopy
the branch of science which studies fingerprints
what portions of the body are covered with small ridges that are raised portions of the skin
fingers, toes, feet, palms and lips
what do the ridges on our fingers do?
help us grip objects
what appears dark on a fingerprint image and what appears light
ridge is dark and valley is light
at what time do fingerprints start to form
10th week of pregnacy
how many layers are the skin
3
what is an arch
the ridge pattern starts from one side of the print and leaves from the other side
what percentage of arch fingerprints are found
5
the center of a loop or whorl pattern is called
core
what is dermal or friction ridges
raised portions of the skin, arranged in connected units, which form fingerprints
what is a delta
triangular ridge pattern with ridges that go in different directions above and below a triangle ( found in all loop and whorl patters)
define fingerprint
impression left on any surface that consists of patterns made by ridges on the tip of a finger
define loop
fingerprint pattern in which the ridge enters from one side, curves, then exits on the same side
loop fingerprints are found in __% of the population
65
define latent
a hidden fingerprint made visible through the use of powders or other techniques
____ is the combination of details in the shapes and positions of ridges in fingerprints that make each unique ( also called ridge characteristics)
minutiae
define patent
fingerprint that happens when fingers with blood, ink, chalk, grease or dirt on them touch a surface and transfers to that surface
what is plastic
three-dimensional fingerprint made in soft material such as clay, soap, paint, putty or wax
what fingerprint pattern resembles a bulls eye
whorl
what percentage of the population has whorl fingerprints
30
what is the outermost layer of the skin
epidermis
the innermost layer of the skin
dermis
what is the basal layer
cells grow faster then the laters above and below so it collapses and folds to form the shapes of a fingerprint
what type of sweat gland is associated with hair follicles
apocrine
type of sweat gland associated with the hands and feet
eccrine
what is the most common fingerprint
loop
least common fingerprint
arch
on the right hand, ______ opens towards the left
radial
this type of arch pattern has a spike in the middle
tented
on the left hand, this loop pattern opens towards the left
ulnar
this whorl pattern is ade up of any two loops combined into one print
double loop
whorl fingerprint type consisting of a combination of two different types of patterns or which conforms to none of the normal fingerprint type definitions
accidental
to be absolutely certain two prints match, they must have __ common minutiae
12
the maximum number of minutiae found to be shared between two different individuals is
8
minutiae pattern that looks like a “y”
bifurcation
method used to lift fingerprints after dusting
tape
super glue fingerprinting method
cyanoacrylate
this fingerprints test results in a purple blue print when amino acids found in sweat react with chemical
ninhydrin
what is silver nitrate
chloride from salt in sweat on a print combines with this to form dark colored prints
fuming this chemical causes fingerprints to appear brown then quickly fade
iodine
fingerprint are ____ type of evidence
individual
what is the method of fingerprinting still used today
galton henry
FBI’s eletronic storage and searcj programs for fingerprints
AFIS
what is the number of fingerprints store in the integrated automated fingerprint identification system
50 million
how long does it take for AFIS to produce a list of potentioal matches from a fingerprint
2 hours
