FKA 2 Flashcards
Describe the nature of Dr. William Babler’s research as it pertains to the prenatal development of the friction skin
It focussed on the understanding of the prenatal morphogenesis of the dermatoglyphic traits and their relationship to birth defects
What is the difference in structure between the basal cells and the primary and secondary ridges
Primary: Basement membrane has a wave like appearance
Keratonocytes have less Keratin
Secondary: Basal cells of the secondary ridges contain long Peg leg projections which extend into the dermis
what are meissner corpuscles
Nerve ending contained in the dermal papillae; establishes the sense of touch the dermal surface
What is the primary cell type of the epidermis
Keratinocytes
What prevents the migration of cells from the basal layer of the epidermis
1) Hemidesmosomes of the basal keeatinocytes
2) Interlocking fibres throughout the basement membrane
What phenomenon ensures that basal cell proliferation is stimulated and inhibited in a coordinated matter
Cell communication
According to Dr Okajima what are 2 subtle changes to the friction skin surface as a person ages
1) surface ridges flatten making them appear less sharp
2) Loss of elasticity in the dermis causes the skin to sag/wrinkle
What causes the puckering of ridges during the formation of a scar an injury site
Contraction of the dermis at the base of the wound/injury
Why is it important for a fingerprint expert to understand the physical limitations of the friction skin
Fingerprint impressions cannot be from the same source if they differ in appearance outside of the actual physical limitations of the skin
According to Dr. Kimura’s research, identify when the prominent flexion creases develop
8 weeks: Thenar creases
9 weeks: Finger creases
10 weeks: toe creases
11 weeks: distal transverse crease
13 weeks: Proximal transverse crease
What is meant by volar pad regression
At the point of slower growth, the contour of the vola pads becomes progressively less distinct and the more rapidly growing surface; the volar pad is overtaken by the faster growth of the surrounding skin as a result of the slower growth of the volar pad
According to Dr Okajima, Chacko and vaidya’s research, when do dermal papillae begin to form and when do they stop
Begin to form at 23 weeks and become more complex through fetal development. Continues onward into adulthood
The onset of cellular proliferation, which begins primary ridge formation, occurs in which 3 distinct areas
1) Apex of the volar pad (core)
2) Tip of the finger near the nail bed
3) Distal inter-phalangeal flexion creases (below deltas)
Name the three main areas of the palm
1) thenar
2) hypothenar
3) interdigital
Name the three groups of flexion creases found in the palm
1) major
- distal (top)
- proximal (middle)
- thenar (bottom)
2) minor
- starburst (by thumb)
- bracelette (crossover/inter-locking)
- by thumbs/finger creases
3) secondary
- cross hatch (horizontal/vertical creases)
- most evident in thenar pad
Name the major palmar flexion creases
1) thenar/radial
2) proximal transverse
3) distal transverse
Can Palmer flexion creases be used for personal identification
Yes. These creases are both unique and persistent and can be used for identification. They should be used with friction ridges for comparisons
What are the basic premises upon which fingerprint identification is based
1) friction ridges develop on the fetus in the definitive form before birth – fully formed by 24 weeks
2) friction ridges are persistent throughout a persons life except for permanent scarring
3) friction ridge patterns and the details in small areas of friction ridges are unique and never repeat
4) friction ridge patterns vary within limits which allows classification
What is the philosophy of fingerprint identification as stated in the I F I M
Identification is established through the agreement the friction ridge formations and accidental characteristics, in sequence, Having sufficient uniqueness to identify them
Name and summarize the methodology you use to individualize a fingerprint
ACE-V - analyze, compare, evaluate and verification
Analyze: Gathering of the objective information regarding the unknown impression to determine if the impression is suitable for comparison by assessing if there are sufficient quantity and quality of detail in the impression
Comparison: Side by side, two stages; what class characteristics are present (digit determination). Reduction in number of sources (exclusion). Determine agreement based on similarity sequences and spatial relationships. Comparative measurements of all types; details sequences and configurations. Consideration of tolerances or variations in appearance (distortions).
Evaluation: based on the analysis and comparison. A clear statement of opinion a must be able to answer; is there agreement in friction ridge detail between the unknown and the know sample? Is there a sufficient agreement in friction ridge detail to identify?
Verification: should be a blind process and is an independent examination using the ACE method by another qualified examiner
What is the purpose of the analysis stage of ACE-V?
Gathering of objective information regarding the unknown impression to determine if the impression is suitable for comparison. Asses anatomical factors, the substrate and matrix, deposition pressure, distortions in level one, two and three detail.
There are three levels of detail which can be observed in the fingerprint oppression. Describe each level and explain it significance to the identification process
1st - overall ridge flow; friction ridges visible, core, Delta and pattern tape
- cannot identify based on first level detail, but can exclude
2nd - ridge paths, ridge features, incipient ridges. Spatial locations of features, scars and creases.
- can identify based on second level detail
3rd - size and shape of the ridges, pores and pore locations
In friction ridge analysis terms, what is vestige
A group of ridges that run parallel to each other and end abruptly at right angles/90° to one another into the surrounding ridges
Salil Chatteejee used the term _____ To describe the examination and evaluation of the edges of friction ridges. Briefly explain its relevance to the fingerprint identification process
Edgescopy: Method of identification through the examination of the unique details and characteristics found along the edges of individual fingerprint ridges
Through heredity, certain traits are passed genetically from parent to child. Why then are fingerprint details not inherited
Heredity can affect things such as pattern type, however, it cannot affect the random formation of friction ridges (stresses, noise, hand position, random timing, random growth)