3) Fingerprint Identification Flashcards
The four premises of Friction ridge identification
1) Friction ridges develop on the fetus in their ______________ ________ prior to birth.
2) Friction ridges are persistent throughout life except for _________________ ______________, ______________, or __________________ after death.
3) Friction ridge paths and the details in small areas of friction ridges are _____________ and __________ _________________.
4) Overall, friction ridge patterns _______ __________ __________, which allow for classification.
Definitive form
Permanent scarring, disease, or decomposition
Unique and never repeated
Vary within limits
What is friction skin also called?
Volar Skin
List some characteristics of the Volar surfaces.
No sebaceous (oil) glands Sweat glands only More sweat glands per square inch than other skin No hair Lack of pigmentation Over-abundance of nerve-endings
When do primary friction ridges start to develop?
At 12 weeks (2nd trimester)
Which layer migrates to the surface of the skin where they are eventually sloughed off as dead skin cells?
The Stratum Basale Layer (the generating layer)
What are the 3 sources of natural secretion o the human body? Which ones are considered significant for fingerprint identification?
Eccrine glands, sebaceous glands, apocrine glands
Eccrine and sebaceous glands
Where are eccrine glands located?
Over the entire body & are the only sweat glands located on the palmar and plantar surfaces.
Where are sebaceous glands found? Expand.
Found on areas of the body associated with hair follicles. Sebum is secreted from these glands (comprised mainly of saturated fats, waxes, and squareness). Although sebum is not produced on palmar and plantar surfaces, it readily migrates and is accumulated there as we touch areas of our bodies where it is excreted.
Name and describe the focal points & pattern types of Level 1 friction ridge detail.
Core: Central area of impression
Delta: Loop pattern, has a triangular formation (called a delta)
Arch: pattern flow from left to right
Loop: ridges entering core area and recurving and coming back down towards same area of origin (one delta on opposite side of origin)
Whorl: like a bullseye, two points of delta
Individuality of a fingerprint is not determined by its general shape or pattern but by _____________.
Minutiae
Level 2 characteristics:
What is a ridge unit (ridge dot)?
Isolated ridge unit whose length approximates its width in size. Contains one pore.
Level 2 characteristics:
What is a Short ridge (Island)?
A single friction ridge beginning, travelling a short distance, and ending.
Level 2 characteristics:
What is a ridge ending (Ending ridge)?
A single friction ridge that terminates within the friction ridge structure.
Level 2 characteristics:
What is a bifurcation (dividing ridge)?
The point at which one friction ridge divides into two friction ridges.
Level 2 characteristics:
What is an enclosure (lake)?
A single friction ridge that bifurcated and rejoins after a short course and continues as a single friction ridge.
