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
There is less keratin in the primary ridges than in the secondary ridges.
The secondary ridges display well-developed cellular projections extending deep into the dermis (dermal papillea).
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
Hemidesmisomes - fibres connecting the basal layer to the basement membrane zone
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
Flattening of the ridges and loss of elascticity
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
In order to understand the physical limitations of the skin when conducting comparisons.
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
The volar pad is not so much shrinking but is overtaken by the faster growth of the surrounding skin
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) Established before birth
2) Persistent throughout life
3) Unique to very small areas
4) Classifiable
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 in sequence, Having sufficient uniqueness to identify.
Name and summarize the methodology you use to individualize a fingerprint
ACE-V - Analisys, Comparison, Avaluation and verification
Analyze: This is a qualitative-quantitative evaluation of the fingerprint taking into consideration: substrate, matrix, development medium, digit determination, distortion, deposition pressure, pattern type and clarity. At this stage the examiner determines the FP’s suitability for comparison.
Comparison: Side-by-side, ridge to ridge, in sequence comparison of the two impressions.
Evaluation: At this stage two questions must be answered: is there agreement in friction ridge detail between the unknown and the know sample? Is there a sufficient agreement to identify? An opinion is reached.
Verification: An independant examiner repeats the process without knowing the opinion reached by the first examiner (blind)
What is the purpose of the analysis stage of ACE-V?
To determine if the impression is suitable for comparison.
There are three levels of detail which can be observed in the fingerprint impression. 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. Typically found in the the thenar area of the palm
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, random pressure, random timing, random growth)