Fingerprints

Question 1

What is a known fingerprint called?

Answer 1

An exemplar

Question 2

What are friction ridges?

Answer 2

Raised portions of the skin (corrugated formations) consisting of one or more connected ridge units of friction ridge skin
Also known as epidermal ridges, papillary ridges and rugae

Question 3

What are the characteristics of friction ridges?

Answer 3

• permanent
• unchanging
• unique
• form at 12-16 weeks gestation (foot 1 week later than hand)
• even identical twins have different friction ridges

Question 4

What are the purposes of friction ridges?

Answer 4

1. Enhance tactile sensitivity

2. Increase pad friction

Question 5

What are ridge patterns classified by?

Answer 5

• general shape
• position within the digit
• relative size
• minutiae

Question 6

What is a delta?

Answer 6

The point nearest the centre of the divergence of the type of lines

Question 7

What is the core?

Answer 7

The innermost position of concentric or loop ridges

Question 8

What is a ridge end?

Answer 8

Where individual ridges come to an end

Question 9

What is a bifurcation?

Answer 9

Where a ridge divides into 2 ridges

Question 10

What is an island?

Answer 10

Any short ridges cut off from others

Question 11

What is a crossover?

Answer 11

Where any ridges appear to cross over each other

Question 12

Loop pattern

Answer 12

• ridges flow in one side, loop around, touch an imaginary line drawn from the delta to the core, and exit on the same side from which it has entered
• has only one delta
• account for 60-70% of fingerprints
• 2 types: ulnar loops and radial loops

Question 13

Whole pattern

Answer 13

• a series of a,most concentric circles
• has 2 deltas
• account for 25-35% of fingerprints
• 4 types: plain whorl, central pocket loop whorl, double loop whorl, accidental whorl

Question 14

Arch pattern

Answer 14

• in an arch pattern, ridges flow in one side and out the opposite
• no deltas
• account for 5% of fingerprints
• 2 types: plain arch and tented arch

Question 15

What are fingerprints useful for?

Answer 15

• latent print comparison
• national police checks
• deceased identification
• immigration
• biometric analysis
• electronic security

Question 16

Mummification and fingerprints

Answer 16

• naturally desiccation can occur where the moisture contents of the tissues is below the level, required for bacterial putrefaction
• fingerprints can be restored from a mummified cadaver through boiling and other processes

Question 17

What is maceration?

Answer 17

Changes to the skin resulting from prolonged exposure to water or moisture

Question 18

What occurs during maceration?

Answer 18

• epidermis becomes disconnected from the der,is
• softened and loosens
• thickens
• becomes wrinkled and white
• exfoliation of the epidermal glove (epidermis disconnected)
• the maceration of a corpse is still useful for fingerprint identification

Question 19

What is congenital polydactyly?

Answer 19

Growth of extra digits

Question 20

What is syndactyly?

Answer 20

Joining of the fingers

Question 21

What is zygodactyly?

Answer 21

Webbing or the fingers or toes (also known as incomplete syndactyly)

Question 22

What is ridges-off-the-edge (Cuspal patterns)?

Answer 22

The ridges of the digits flow upwards rather than form whorls or loops (usually classified as tented arches)

Question 23

What is ridge hypoplasia?

Answer 23

Ridges are reduced in height, often combine with and excess of ‘white lines’ on the prints

Question 24

What is ridge aplasia (adermatoglyphia)?

Answer 24

Inherited absence of epidermal ridges

Question 25

What are dissociated ridges?

Answer 25

Ridges form, but do not consolidate into continuous ridges

Question 26

What are split ridges?

Answer 26

Spacing between the ridges is larger than usual, giving the appearance of being split or paired

Question 27

What is a fingerprint?

Answer 27

A reproduction on a surface of palmar or plantar friction ridges

Question 28

What is a latent fingerprint?

Answer 28

Made in perspiration (or other clear foreign matter such as grease form hair oil) and is not readily visible until developed

Question 29

What are visible (patent) fingerprints?

Answer 29

Made in paint, blood or other foreign matter and are easily visible to the human eye

Question 30

What are moulded fingerprints?

Answer 30

Made in a soft substance such as putty, dust, thick grease or wax etc. also known as plastic prints

Question 31

What are etched fingerprints?

Answer 31

Where the acidic nature of perspiration has eroded into a soft metal such as brass or copper

Question 32

What has to happen for a print to occur?

Answer 32

1. A sufficient amount of perspiration (or contaminant) must be transferred from the ridge skin to the surface on contact 2. The surface must not destroy or dissipate the fingerprint deposit (I.e. not excessively dirty, wet, heavily textured etc) 3. The perspiration (or skin matter) must have a sufficient lifespan (I.e. remain present long enough to be discovered)

Question 33

What are the factors that affect the lifespan of a print?

Answer 33

1. Composition 2. Amount 3. Receiving surface 4. Position 5. Environment 6. Time

Question 34

How are surfaces onto which fingerprints are deposited divided?

Answer 34

Porous and non porous

Question 35

What is the most common developer?

Answer 35

Powder

Question 36

What is the identification methodology?

Answer 36

ACE-V

Question 37

What does ACE-V stand for?

Answer 37

Analysis Comparison Evaluation Verification

Question 38

Analysis

Answer 38

The developed impressions are examined to ascertain if there is enough detail to proceed

Question 39

Comparison

Answer 39

- introduces the exemplar with which the latent print is to be compared - analysis of the exemplar also occurs

Question 40

Evaluation

Answer 40

3 outcomes: 1. Identification: unknown impression made by same person as known impression 2. Exclusion: unknown impression not made by same person as known print 3. Undetermined: insufficient information in the known or unknown to form and opinion

Question 41

Verify

Answer 41

All identifications must be independently verified by a second qualified expert

Question 42

What is the minimum number of matching points required to identify an individuals fingerprints?

Answer 42

There is no minimum