Unit 3: Fingerprints

The Dermis

What layer of skin determines fingerprints?

Papillae in dermis bumping up into the epidermis

What part of the dermis determines fingerprints?

Palms and soles

Where are friction ridges found?

The papillae in the dermis bumping up into the epidermis

How are friction ridges created?

During embryonic development, by the end of the 4th gestation month

When do fingerprints form?

The fetus touching things

How do fingerprints form in the womb?

Impressions of friction ridges, the space between rides fills with oil and sweat that is left behind

What creates fingerprints?

Patent prints

Type of print visible to the naked eye, left behind in materials or on things

Latent prints

Type of print not visible to naked eye and must be treated to be seen

60-65%

Prevalence of loop fingerprint

30-35%

Prevalence of swirl fingerprint

5%

Prevalence of arch fingerprint

Loop fingerprint

the ridges enter from either side, re-curve and pass out or tend to pass out the same side they entered

Loop fingerprint

?

Swirl fingerprint

the ridges are usually circular and no not enter or exit

Swirl fingerprint

?

Arch fingerprint

the ridges enter from one side, make a rise in the center and exit in general on the opposite side

Arch fingerprint

?

Bifurcation

Minutiae that is a split or where two ridges come together

Bifurcation

5?

Ridge Ending

the point where a ridge ends abruptly

Ridge Ending

4?

Island

a single small ridge inside a short ridge or ridge ending that is not connected to any other ridges

Island

3?

Crossover

a connecting friction ridge made up of two bifurcations; two ridges cross each other at one point

Crossover

7?