Unit 6: Fingerprinting Flashcards
What is the study of fingerprinting for identification purposes called?
Dactylography or dactyloscopy
Which parts of your body have fingerprints?
Fingers, toes, feet, palms, and lips
What are the raised portions of the skin called?
Dermal or friction ridges
What do ridges help one with?
Help us to grip objects also have the most nerve endings
How does a ridge appear on a fingerprint?
It appears dark and a valley appears light
When do fingerprints begin to form?
Around 10 weeks of pregnancy, when the fetus is 3 inches long (in a fetus, the basal layer cells grow faster than the other layers above and below it, so it collapses and folds to form shapes)
What makeup the 3 layers of skin:
- Inner layer: dermis
- Outer layer: epidermis
- Layer in between: basal layer
Where does fingerprint residue originate from?
From the glands in the subcutaneous skin
What are the two glands responsible for the fingerprint residue also known as the sweat glands?
Apocrine and eccrine glands
What are apocrine glands associated with?
Hair follicles (like top of alphabet on head)
What are eccrine glands located?
Ridges of the hand and feet
What are the two things that a forensic examiner looks for?
- Core (center of a loop or whorl)
- Deltas (a triangular region located near a loop)
What are the three types of fingerprint patterns?
- Loop
- Whorl
- Arch
What are the types of arches?
- Plain arch: ridges enter one side and exit on the other
- Tented arch: has a spike in the center
Types of loops?
These patterns are named for their positions related to the radius and ulna bones:
- Radial loop (right thumb): loop opens towards the left or the radial bone (on left-hand side)
- Ulnar loop (right thumb): loop opens towards right of the ulna bone opens towards ulna bone
Types of whorls?
- Plain whorl (one or more ridges that make a complete circuit, with 2 deltas)
- Central pocket whorl (one recurring edge, or obstruction at a right angle to the line of flow)
- Double loop whorl (made up of any 2 loops combined)
- One print (like yin-yang)
- Accidental (does not clearly fall into any other categories)
Does every person, including twins have individual fingerprints?
Every individual has a unique fingerprint resulting from unique ridge patterns called minutiae (called this because the details are so minute or small)