"How Stuff Works-Why do we have fingerprints?"

[Cindy Homer]

I don't know if anyone reads this site but I ran across this a while ago on Facebook and once again last night. It's another "article" on error rates and the supposed unreliability of fingerprints. I wanted to pass along the link so you are at least aware of its existence.

http://science.howstuffworks.com/life/h ... prints.htm

[Les Bush]

This article is not only about error rates but it proposes a certain fundamental theory of fingerprint formation as explained by CLAIBORNE RAY and printed in the New York Post Science section. There is more than one theory about how fingerprints form with significant scientific support available to argue the basis of understanding. When we look at fingerprints we see a uniform arrangement of ridges evenly spaced and evenly raised. The physical pattern of fingeprint details is representative of the process of alignment of nerve tissues that make up the sophisticated sense of touch. The balanced distribution and variety of nerve tissue types is by far a higher order biological priority and superior to the random chaos activity of the biomechanical theory. Fingerprint science experts really do need to address this issue of divergent theories as it represents the fundamental principle of how uniqueness of fingerprint details are produced. Cheers from oz Les

[Cindy Homer]

Hi Les,
I am not finding any reference by Ray in the attached article having to do with innervation nor can I find anything online where he references it. The only things I can find that he cites have to do with mechanical forces and stress. Could you give some references/link/etc. so I can have a look at where he is writing about this and what he is citing? Kasey Wertheim goes into the innervation proposal in his chapter of the Sourcebook. I'm specifically asking what resources Ray is citing. Anything new/different? Thanks! Cindy

[Les Bush]

Hello Cindy,

Your request about innervation information will not be found in the NYTimes article by Claiborne Ray (Twins and Fingerprints). What he proposes is the biomechanical theory, with stresses and pressures causing random activities that make all fingeprint patterns unqiue. The How Stuff works article follows the same understanding and my main point is that this is practically a universal acceptance of how fingerprints form, mainly because it is what fingerprint experts are mostly taught. The Source book article by Kasey underlines that teaching, he also cleverly introduces the concept of innervation as a possible cause but leaves it hanging in the breeze of possibility, much the same as David Ashbaugh has done in his text book.

I was never happy with the theory of biomechanical causation as it seemed too much a 'blind' process that somehow incredibily delivered a sophisticated outcome. We all have unique fingerprint patterns of detail, the various patterns and arrangements of features encompassed by a majority of continuous ridges. But remarkably those same patterns 'all' have uniform and measurable spacing between ridges and these same ridges have a uniform measurable height above the surface of the epidermis. To me that means there must be some control and reason for having these predictable outcomes. The answer cannot be found in the biomechanical theory and it also talks about 'ridge unit fusion' which is biologically difficult to accept. Biology 101 will doubt that tissues of ridge units fuse together, it is epithelium cells that can 'join' together to form tissues using junctions such as desmosomes, thats how biology works. The anatomy of a ridge unit as defined, is also only formed after 16 weeks onwards when dermal pappilae start forming and the epidermis has differentiated into five stratum. Given the variety of tissues involved the expression of ridge unit fusion to support the biomechanical theory is doubtful.

If you are looking for innervation reference material, you could start with my small collection of research papers (Golden Hands and Silver Feet) which I assume could now be expanded with more contemporary articles. Unfortunately the science world has lost a great researcher in Bryce Munger particulary for helping our fingerprint community. A link to an article on innervation is attached. If it doesnt open try a Goolge search, 'les bush fingerprints'.
http://www.latent-prints.com/images/Fin ... 20skin.pdf

In the USA are several experts who have copies of the complete research articles and reference materials. As I have retired from Forensic Science I no longer have access to library resources to continue the research. Cheers from oz, les

[Cindy Homer]

Hi Les,
Thank you for your explanation and the article. Was it ever published? I've never seen it before. I'll read it over and let you know if I have any questions. Thank you for passing it along.

I teach at a local university and have access to many journals. If you're looking for something in particular let me know. I will see if I can find it for you.

Cindy

[Les Bush]

Hi Cindy,

The question re publications was a journey beginning with Golden Hands and Silver Feet, the collection of papers were a summary of subjects and without the use of images would have been less informative. The first problem was the acquiring of copyright permissions, some publishers responded others didnt. Then it became a question of costs. In the end I released the work in 2011 as an internal organisational educational paper unpublished. After that point I was getting closer to retirement and any additional papers like the one attached to this thread were also released without publication or review. I did take the step of producing a number of DVD copies of the papers and distributed them to colleagues in the USA so I'm confident readers of this site would be some of the recipients and perhaps the Website could include them if there was enough interest.

My work background is both Crime Scenes and Fingerprints and the final years of Policing were more Crime Scene based so I didnt progress this research right to the end. I was always hoping someone or a group would take up the mantle and continue the line of inquiry.

Thank you for your offer to access further papers, the PubMed site was always helpful and I would still be interested in reading and reviewing papers relating to embryo/foetal development, post 2010/11, with focus on the neurological distribution on palmer and plantar surfaces. The group that were mentored by Bryce Munger were heading in the right direction to claim the basis of fingerprint patterning is reliant on the map of nerves under each friction ridge. Cheers again from oz. Les

[Les Bush]

Hello Cindy,

Once an investigator, always an investigator, just by commenting on research has caused a new interest to happen once again. I had a quick look at Pub Med and found the following article, which may be of interest to you and those who are looking for authoritative articles on fingerprint development. If you happen to acquire the full article please send it over by email or if Kasey and Steve agree if could go on their library page.

Med Hypotheses. 2010 Aug;75(2):162-8. doi: 10.1016/j.mehy.2010.02.011. Epub 2010 Mar 1.
Multifunctional Merkel cells: their roles in electromagnetic reception, finger-print formation, Reiki, epigenetic inheritance and hair form.
Irmak MK.
Author information
Abstract
Merkel cells are located in glabrous and hairy skin and in some mucosa. They are characterized by dense-core secretory granules and cytoskeletal filaments. They are attached to neighboring keratinocytes by desmosomes and contain melanosomes similar to keratinocytes. They are excitable cells in close contact with sensory nerve endings but their function is still unclear. In this review, following roles are attributed for the first time to the Merkel cells: (1) melanosomes in Merkel cells may be involved in mammalian magnetoreception. In this model melanosome as a biological magnetite is connected by cytoskeletal filaments to mechanically gated ion channels embedded in the Merkel cell membrane. The movement of melanosome with the changing electromagnetic field may open ion channels directly producing a receptor potential that can be transmitted to brain via sensory neurons. (2) Merkel cells may be involved in finger-print formation: Merkel cells in glabrous skin are located at the base of the epidermal ridges the type of which defines the finger-print pattern. Finger-print formation starts at the 10th week of pregnancy after the arrival of Merkel cells. Keratinocyte proliferation and the buckling process observed in the basal layer of epidermis resulting in the epidermal ridges may be controlled and formed by Merkel cells.

Cheers from oz. Les

[Les Bush]

Hi Cindy,

Christophe Champod is an academic who has been interested in Forensic Science and fingerprints for quite some time. He like yourself is also a universtity lecturer. This article would be of interest. In case you have followed the McKie Inquiry it was Christophe who was selected as an authority for science related issues about fingerprints.

J Theor Biol. 2013 Jan 21;317:229-37. doi: 10.1016/j.jtbi.2012.10.009. Epub 2012 Oct 16.
Merkel cells and the individuality of friction ridge skin.
Kücken M, Champod C.
Author information
Abstract
There is no definite theory yet for the mechanism by which the pattern of epidermal ridges on fingers, palms and soles forming friction ridge skin (FRS) patterns is created. For a long time growth forces in the embryonal epidermis have been believed to be involved in FRS formation. More recent evidence suggests that Merkel cells play an important part in this process as well. Here we suggest a model for the formation of FRS patterns that links Merkel cells to the epidermal stress distribution. The Merkel cells are modeled as agents in an agent based model that move anisotropically where the anisotropy is created by the epidermal stress tensor. As a result ridge patterns are created with pattern defects as they occur in real FRS patterns. As a consequence we suggest why the topology of FRS patterns is indeed unique as the arrangement of pattern defects is sensitive to the initial configuration of Merkel cells.
Copyright © 2012 Elsevier Ltd. All rights reserved.

[Les Bush]

Hi Cindy,

I will go quiet shortly, this article is a primary example of the work of Bryce Munger and would be at the centre of any theory relating nerve mapping to friction ridge development.

Brain Res Dev Brain Res. 1989 Jul 1;48(1):119-41.
The early ontogeny of the afferent nerves and papillary ridges in human digital glabrous skin.
Moore SJ, Munger BL.
Abstract
The present study examines the early ontogeny of afferent nerves in human embryonic glabrous digital skin and documents the onset of cutaneous innervation and papillary (sweat duct) ridge formation by light and electron microscopy. The skin examined in this study was taken from 3 developmental stages of decreasing embryonic age: embryos older than 10 weeks estimated gestational age (EGA) representing the period of primary ridge formation, embryos of 8-9 weeks EGA representing the period immediately prior to ridge formation; and embryos 6-8 weeks EGA representing the period weeks before the onset of ridge formation. The earliest papillary ridges are present in 10 week EGA embryos, with small ridges present in two sites: the center of the proximal third and also at the tip of the distal phalangeal or apical pad. These papillary ridges typically contained Merkel cells. Papillary ridges formed progressively in a radial manner from these central foci. The proximal focus corresponds to the geometric center of the mature dermatoglyphic pattern of loops, arches, or whorls. This radial wave of ridge differentiation is discontinuous with the abrupt cessation of ridge formation responsible for the discontinuities in the mature papillary ridges and the corresponding dermatoglyphic print. Skin over the proximal and middle phalanges developed papillary ridges beginning in the 12th week. No papillary ridges could be identified in embryos of 8-9 weeks EGA, but a large number of growth cones are present in the superficial dermis subjacent to differentiating Merkel cells. The basal lamina of the epidermis was discontinuous wherever growth cones abutted Merkel cells. Merkel cells not directly associated with axons were also present in the epidermis of embryos of 8-9 weeks EGA. The embryos of 6-8 weeks EGA lack any sign of Merkel cells and/or melanocytes, but developing neurovascular bundles with axonal growth cones near the epidermis could be identified by light and electron microscopy. Presumptive Schwann and perineural cells are also seen in the dermis.

We conclude that the developing afferent nerve fibers provide a grid which influences the temporal and/or spatial factors involved in the sequential onset and cessation of formation of papillary ridges. Thus the dermatoglyph can reflect the ontogeny of the afferent nervous system that occurred prior to papillary ridge development. These observations lend support to the concept that successive waves of afferent neural development have an important role in the spatial and temporal sequence of papillary ridge formation and thus the formation of both the dermatotopic map of the digits and the dermatoglyph. Cheers from oz. Les

[Les Bush]

Hi Cindy,

This will definitely be my last posting on this thread, over 600 views but no comments so the fish are there just not interested.

Sheibert et al did a great job replicating the geo spatial arrangement of fingerprint ridges, without the individual details just using the distance between ridges and uniform height above the base. Their work strongly supports the anatomical outcome that fingerprints are directly related to the needs of the nervous system. This biological priority is at work in the embryo at a time prior to the formation of primary ridges and is only complete when the full structure of the surface ridges are realised. The following is an absract on the Science web site. Cheers from oz. Les

THE ROLE OF FINGERPRINTS IN THE CODING OF TACTILE INFORMATION PROBED WITH A BIOMIMETIC SENSOR

In humans, the tactile perception of fine textures (spatial scale <200 micrometers) is mediated by skin vibrations generated as the finger scans the surface. To establish the relationship between texture characteristics and subcutaneous vibrations, a biomimetic tactile sensor has been designed whose dimensions match those of the fingertip. When the sensor surface is patterned with parallel ridges mimicking the fingerprints, the spectrum of vibrations elicited by randomly textured substrates is dominated by one frequency set by the ratio of the scanning speed to the interridge distance. For human touch, this frequency falls within the optimal range of sensitivity of Pacinian afferents, which mediate the coding of fine textures. Thus, fingerprints may perform spectral selection and amplification of tactile information that facilitate its processing by specific mechanoreceptors.

[Tazman]

. . . over 600 views but no comments so the fish are there just not interested. . . .

Perhaps I might suggest that metaphor is not entirely accurate.

The simple fact the students do not ask questions when 600 of them sit in rapt attention does not mean they are not learning.
Keep up the good work of teaching us, Les. Please.

Cheers, Tazman

[Les Bush]

Hello Tazman,

I could go on finding interesting articles and posting abstracts and the fish could enjoy a nibble or two. Ofcourse some fish will come back more than once so the number of 600 could realistically be rounded down to about 200 or even less. To motivate me to do more would require knowing what is the true class size? Also the ocean of the world wide web will require a common place from which you can join in. My research papers have been distributed fairly widely to associates in Europe and North America and Australia so I'm sure if some webmaster is keen to provide the venue and information resources we could start a forum or thread and begin again. There were two things I had in mind when compiling the research, firstly to give me as an expert a realistic understanding of the science of fingerprints and secondly to produce a logical sequence of knowledge from fundamental principles through to the identification process. This approach is not new to the way fingerprint science has evolved over its history since before 1900 and what one person may now call dogma another would say why change what is apparently working. To be a truly objective researcher is to challenge all assumptions and test many hypothesis until the real picture emerges. I still enjoy reading the classic novel, Jonathan Livingston Seagull and for those who have also read it you will understand the angle of my motivation. Cheers from oz. Les

“Don’t believe what your eyes are telling you. All they show is limitation. Look with your understanding. Find out what you already know and you will see the way to fly.”
― Richard Bach, Jonathan Livingston Seagull