4.16: OTHER CONSIDERATIONS
- Page ID
- 52995
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Comparing unknown to know
As previously mentioned, it is advisable to always compare the unknown print to the exemplar print, and not the other way around. This is because the brain is capable of capturing a brief memory of the known print, which will then transpose that memory to unknown print. Although it is possible to happen when comparing the unknown print to the known, that feature on the unknown print will likely not be transposed onto the known print without the analyst noting the discrepancy.
Scars
Scars are exceptionally unique identifiers in a fingerprint. It would be exceedingly unlikely that two people with the same fingerprint pattern and notable minutiae could cut themselves deeply enough in the exact same place on the finger to leave a scar. If a person cuts themselves only at the epidermal layer of ridge-print skin, the ridges grow back exactly as before. However, if a person cuts themselves deep into the dermal layer of ridge-print skin, the ridges do not grow back, and the scar becomes a distinguishing feature. The scar is notable by an inward “puckering” where the ridges appeared to be falling into the furrow created by the scar. This is how scars are differentiated from creases.
Adermatoglyphia
There is a rare genetic skin condition where ridge-print skin does not develop during the volar stage of fetal development. This condition is called adermatoglyphia. Depending on the degree of adermatoglyphia, the individual may not be identified using fingerprints and therefore DNA would be the best alternative method of identification. However, many years ago, your author was tasked with identifying an adermatoglyphic person by the ridge impressions in figure \(\PageIndex{2}\). In this case, your author was able to create a transparency of the print and then over the transparency with the exemplar print. Each dot that matched the overlay was one point of minutiae, and an identification was able to be made.
Incipient Ridges
Another very unique identifier within the ridge pattern is the incipient ridge. Incipient ridges, also called nascent ridges, are immature ridges that began development, but for some reason never fully developed. These ridges are often found between two ridges, and appear as very small or thin ridges, as in figure \(\PageIndex{3}\).
Is it a dot or dirt?
Your author maintains there is no such thing as a perfect fingerprint. Often, latent print examiners will ask themselves, “Is this an end ridge or a bifurcation that did not develop or ink, or is it a dot or dirt?” The answer to these questions can be found by examining the ridges above and below the ridge in question. If you look at the ridges above and below the short ridge in Figure 4.40, you will notice that the ridges tend to bow away from the short ridge. The same will occur with a dot or end ridge. Therefore, if it looks like an end ridge that is leaning towards another ridge, and the ridge above or below does not bow away from the ridge, it is likely that the ridge is a bifurcation with an undeveloped or recorded connecting ridge.
