Volar Pads Research Articles

LYMPHSPIRATION THE IMPORTANCE OF THE STUDY OF DERMATOGLYPHICS FOR LYMPHOLOGISTS

A recent genome-wide association study (GWAS) looking for the genes determining fingerprint and palmar crease patterns disclosed one gene, among many others, which causes lymphedema (CELSR1) while others influencing tissue growth. Since digital fluid influences the height of the volar pads, influences of lymphedema on dermatoglyphics should be sought.

Longitudinal study of rat volar fat pad fixation and ethanol storage: implications for the use of fluid-preserved specimens in morphological studies.

Museum fluid collections preserve important biological specimens for study. Tissues are often fixed in 10% buffered formalin to halt metabolic activities and transferred to a solution of ethanol for long-term storage. This process, however, forces water from the tissues and has been shown to alter the morphology of preserved specimens in ways that may influence the biological interpretation of results. The degree to which fluid preservation alters morphology is linked to multiple biological factors, such as tissue size and composition, and should therefore be examined prior to functional analysis. This study is undertaken as part of a more inclusive examination of mammalian volar morphology. A sample of five adult male and five adult female rats (Rattus norvegicus) was utilized to evaluate longitudinal changes in the dimensions of the volar pads across fixation in 10% buffered formalin and preservation in 70% ethanol for 1 year. No significant changes to the measured dimensions of the rat volar pads were present across stages of fixation and preservation, and no significant interactions of specimen size or sex were noted. These findings indicate that small mammalian volar pads that have been fixed in 10% buffered formalin and stored in 70% ethanol are appropriate for morphological study using the measurements described here without corrective algorithms. This finding is rare among preservation studies but highlights the variability of tissue behavior during chemical preservation and the necessity of preliminary investigations of preservation artifacts. Concurrence here between the preserved and unpreserved samples is likely related to the anhydrous nature of the volar pads and the supporting skeletal structure, and their confined position between major joints of the hands and feet.

Barrels of Monkeys: Effects of Long‐term Ethanol Storage on Volar Fat Pad Morphology

Museum fluid collections preserve tissues from endangered and protected species for study. Tissues are often fixed in 10% buffered formalin to halt metabolic activities and transferred to a solution of ethanol for long term storage. This process, however, forces water from the tissues and has been shown to alter the morphology of preserved specimens in ways that may influence the biological interpretation of results. The degree to which fluid preservation alters morphology is linked to multiple biological and methodological factors and should therefore be examined prior to functional analysis. This study was conducted as part of an evaluation of mammalian volar pad morphology and comprises two analyses. In the first, a sample of rats (Rattus norvegicus) is utilized to evaluate longitudinal changes in the dimensions of the volar pads across fixation in 10% buffered formalin and preservation in 70% ethanol for one year. In the second, a cross‐sectional sample of fresh primate volar pads from varying species is compared to a corresponding sample from museum specimens fixed in 10% buffered formalin and preserved in 70% ethanol. No significant changes to the measured dimensions of the volar pads are present across stages of fixation and preservation, nor are significant differences evident between fresh and preserved specimen groups. These findings are likely related to the anhydrous nature of the volar fat pads and their confined position between major joints.Support or Funding InformationThis work was funded by NSF Doctoral Dissertation Improvement Grant #1128861.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Digital diabetes?

S Yohannes, et al. Dermatoglyphics in diabetes: a prospective diagnostic aid and early preventive tool. Pages 50– 51. We have friction ridges on the skin of our finger tips – our fingerprints. These develop on the smooth fetal volar pads. The patterns formed vary according to the rate of hand growth versus volar pad regression. Genetic factors influence the timing of these events and thus the ultimate fingerprint pattern, so family members, particularly identical twins, share a similar pattern type. However, in each person the exact arrangement of the friction ridges and any subsequent scarring mean that their fingerprints are unique. Intrauterine undernutrition has been linked to adult type 2 diabetes1 which is often strongly inherited, so it seems logical to consider if fingerprints, also influenced by these factors, can be used as a marker for risk of future diabetes. In people born during the Dutch hunger period (1943–47), with adjustment for age, sex, parental diabetes and adult anthropometry, fingerprint mean dermatoglyphic ridge count difference between fingertips 1 and 5 (Md15) was associated with prevalent diabetes odds ratio of 1.37 (1.02–1.84). ‘Among 42 sibling pairs discordant for diabetes, the diabetic sibling had higher Md15 by 3.5 (0.6–6.3) after multivariable adjustment.’2 However, many paths lead to diabetes, with different genetic factors and different effects of nutrition inside or outside the womb. There are probably hundreds of versions of diabetes. So, in this issue of Practical Diabetes, Yohannes et al. are right to point out that very carefully controlled studies are needed. Patients have a practical issue: ‘I had to have my fingerprints done recently. The guy was all cheery and polite… until I had to show him my hands. He asked what all the “dots” on my left hand fingers were from so we had a little conversation about diabetes, the pump, testing… Then, he says, “oh, well that's going to make the prints bad and there's nothing I can do about it. The prints probably won't turn out and you'll have to come back up here to do it again”.’3 Small scars on the fingertips should not invalidate fingerprint testing; indeed, it may make people more readily identifiable!

The evolution of the hominin thumb and the influence exerted by the non-dominant hand during stone tool production

Modern humans possess a highly derived thumb that is substantially stronger and more robust than the fingers. Previous hypotheses concerning the evolution of such traits have focused upon the manipulation of hammerstones during stone tool production and of stone tools during their use. To date there has been no research on the manipulative pressures exerted by the non-dominant (core-holding) hand during stone tool production and its potential influence on the evolutionary history of the thumb. Here we provide the first investigation into the frequencies of digit recruitment and the relative manipulative forces experienced in the non-dominant hand during stone tool production. Eight experienced knappers produced flake cutting tools under four distinct conditions while pressure sensors, secured to the volar pads of the thumb, index and middle fingers of the non-dominant hand, recorded manipulative forces. Results indicate that relative to the fingers, the thumb was recruited significantly more frequently and experienced significantly greater manipulative forces during core repositioning events and the securing of the core during flake detachments. Our results support the hypothesis that the robust thumb anatomy observed in the hominin lineage was selected for, at least in part, as a result of more frequent and greater manipulative pressures acting upon the thumb relative to the fingers on the non-dominant hand during stone tool production.

Obligate exudativory characterizes the diet of the pygmy slow loris Nycticebus pygmaeus

Few primate species are known to excavate plant sources to procure exudates and other foods via active gouging. It is now apparent that slow lorises belong to this rare guild of obligate exudativorous primates. We investigate the diet of the pygmy loris (Nycticebus pygmaeus) in a mixed deciduous forest in the Seima Protection Forest, Eastern Cambodia, and attempted to determine the importance of this resource in their diet. Feeding behaviors of six females and seven males were observed using radio-tracking to facilitate follows, and nine fecal samples were collected in February-May and January-March in 2008 and 2009 respectively. We observed 168 feeding bouts, during which the animals ate exudates (76); fruits (33); arthropods (27); flower parts (21); fungi (3); parts of bamboo culms (7); and reptiles (1). We filmed 19 bouts of exudativory, and observed animals consuming exudates in an orthograde posture, or standing quadrupedally over the exudate source. Pygmy lorises also gouged bamboo to collect lichen and fungi, or broke open dead culms to access invertebrates. Feeding occurred on terminal tree branches (24), tree trunks (21), bamboo (13), the middle of branches (7), and the undergrowth (1). The fecal samples contained plant parts, small-sized arthropods (primarily Coleoptera and Lepidoptera), reptile scales, animal bones, and animal hairs. Pygmy slow lorises are morphologically specialized for processing and digesting exudates, displaying small body sizes, specialized dentitions, elongated, and narrow tongues, large caecums, short duodenums, expanded volar pads, and modified hindlimbs. These features, combined with the prevalence of exudates in their diet across seasons, and ill health when exudates are missing from their diet in captivity, points to this species being an obligate exudativore.

Fingerprints: Historical Background And Future Trends

The work of police, judges, and juries would be much easier if criminals left signed confessions at the scenes of their crimes. That seldom happens, of course, but criminals often do leave identifying “signatures” in the form of fingerprints. No two people, not even identical twins, have ever been shown to have exactly the same pattern of raised, curved lines on their fingertips. Each individual possesses a unique set of minute raised ridges on volar pads called ‘friction ridge skin’. These clear and apparent unique outlines of the ridges are called fingerprints. A fingerprint is highly individualistic and forms the basis for personal identification in forensic examinations.

Quantitative digital and palmar dermatoglyphics: Sexual dimorphism in the Chuvashian population of Russia

With the aim of determining sex dimorphism among the Chuvashian population of Russia, digital and palmar dermatoglyphics of 547 individuals (293 males, 254 females) were analyzed. The sex differences for PII, TRC, and AFRC are similar to Indian and Jewish populations. Correlation coefficients between individual finger ridge counts are a little lower than in Jews but are almost equal to Indian populations. The Mantel test of matrix correlation between sexes for 22 traits shows a very good similarity. However, sex differences of palmar traits display different levels when compared with other human populations. In light of this, our evidence indicates the possible role of environmental (prenatal) factors in the realization of dermatoglyphic sex differences. The development of palmar dermatoglyphics has had a relatively longer growth period compared with fingers [Cummins, H., 1929. The topographic history of the volar pads (walking pads, tast ballen) in the human embryo. Embryol. 20, 103–126]. The palmar dermatoglyphic pattern of affinities therefore corresponds better than fingers to the ethno historical background of the populations, ascertained by numerous studies.

Ectopic dermal ridge configurations on the interdigital webbings and postaxial marginal portion of the hindlimb in Hammertoe mutant mice (Hm)

The effects of the hereditary malformation of Hammertoe mutant mice (gene symbol Hm) on the digital pads and dermal ridge configurations on their hindlimbs were examined. In the wild-type (+/+) mice with normally separated digits, dermal ridges developed only on the pads. Heterozygous (Hm/+) and homozygous (Hm/Hm) mutant mice, however, had a broad big toe, fused interdigital soft tissues, reduced claws, an extra rudimentary postaxial digit and camptodactyly. The dermal ridges appeared not only on the pads, affected in their number and configurations, but also on the ventral surface of the interdigital webbings and postaxial marginal area exhibiting an extra rudimentary digit and webbing. These aberrant configurations may be related to the abnormal occurrence of programmed cell death (PCD) in the interdigital zones and the postaxial marginal portion in Hm/+ and Hm/Hm mice. That is, the diminished cell death may fail to decrease the cell density in the interdigital zones and postaxial marginal portion and result in the webbing and an extra rudimentary digit and webbing, respectively. Simultaneously, it could also interrupt the migration of surviving cells of these areas toward the neighboring digits and the distal area of the sole and produce the ectopic dermal ridges on the way to the as yet unformed (presumptive) digital and plantar volar pads. The present findings suggest that normal interdigital and pre/postaxial PCD contributes not only to the separation of digits, the initial formation of individual digits of different sizes, and the inhibition of the extra digit but also to the development of the presumptive digital and plantar pads, including dermal ridges.

A fingerprint characteristic associated with the early prenatal environment

Fingerprints and fingertip ridge counts (RCs) have a significant genetic component. However, they also reflect the nongenetic environment of early pregnancy, an important time window for tissue differentiation and organogenesis. Fingerprints are permanently configured before the 20th week of gestation, and each fingertip's RC is related to the growth and regression of its early fetal volar pads. Rostral and caudal aspects of the embryonic limb bud have different relations to somite segments and to morphogen-activator functions. We hypothesized, therefore, that early fetal circumstances would be associated with a contrast in RCs between the thumb (digit 1) and little finger (digit 5). We obtained RCs from the fingerprints of a sample of 658 Dutch adults identified through prenatal and delivery records of Dutch urban births occurring during 1943-1947, an historical era that included months of wartime disruption with a winter famine. We calculated the mean of left- and right-hand RC differences between digits 1 and 5 (Md15). The Md15 fluctuated in relation to the calendar season of the mother's last menstrual period, but only if the gestation occurred outside of the wartime disruption interval. If the gestation occurred during the disruption interval, the Md15 seasonal fluctuation was not evident. This finding suggests that parental environmental factors may influence the fingerprints of the offspring. Fingerprint RC differences observed in postnatal life may be useful in the study of metabolic or anatomic programming related to the early prenatal environment.

Body size and scaling of the hands and feet of prosimian primates

The hands and feet of primates fulfill a variety of biological roles linked with food acquisition and positional behavior. Current explanations of shape differences in cheiridial morphology among prosimians are closely tied to body size differences. Although numerous studies have examined the relationships between body mass and limb morphology in prosimians, no scaling analysis has specifically considered hand and foot dimensions and intrinsic proportions. In this study, we present such an analysis for a sample of 270 skeletal specimens distributed over eight prosimian families. The degree of association between size and shape was assessed using nonparametric correlational techniques, while the relationship between each ray element length and body mass (from published data and a body mass surrogate) was tested for allometric scaling. Since tarsiers and strepsirrhines encompass many taxa of varying degrees of phylogenetic relatedness, effective degrees of freedom were calculated, and comparisons between families were performed to partially address the problem of statistical nonindependence and "phylogenetic inertia." Correlational analyses indicate negative allometry between relative phalangeal length (as reflected by phalangeal indices) and body mass, except for the pollex and hallux. Thus, as size increases, there is a significant decrease in the relative length of the digits when considering all prosimian taxa sampled. Regression analyses show that while the digital portion of the rays scales isometrically with body mass, the palmar/plantar portion of the rays often scales with positive allometry. Some but not all of these broadly interspecific allometric patterns remain statistically significant when effective degrees of freedom are taken into account. As is often the case in interspecific scaling, comparisons within families show different scaling trends in the cheiridia than those seen across families (i.e., lorisids, indriids, and lemurids exhibit rather different allometries). The interspecific pattern of positive allometry that appears to best characterize the metapodials of prosimians, especially those of the foot, parallels differences found in the morphology of the volar skin. Indeed, relatively longer metapodials appear to covary with flatter and more coalesced volar pads, which in turn slightly improve frictional force for animals that are at a comparative disadvantage while climbing because of their larger mass. Despite the essentially isometric relationship found between digit length and body mass across prosimians, examination of the residual variation reveals that tarsiers and Daubentonia possess, relative to their body sizes, remarkably long fingers. Such marked departures between body size and finger length observed in these particular primates are closely linked with specialized modes of prey acquisition and manipulation involving the hands.

Fingerprint formation

Fingerprints (epidermal ridges) have been used as a means of identifications for more than 2000 years. They have also been extensively studied scientifically by anthropologists and biologists. However, despite all the empirical and experimental knowledge, no widely accepted explanation for the development of epidermal ridges on fingers, palms and soles has yet emerged. In this article we argue that fingerprint patterns are created as the result of a buckling instability in the basal cell layer of the fetal epidermis. Analysis of the well-known von Karman equations informs us that the buckling direction is perpendicular to the direction of greatest stress in the basal layer. We propose that this stress is induced by resistance of furrows and creases to the differential growth of the basal layer and regression of the volar pads during the time of ridge formation. These ideas have been tested by computer experiments. The results are in close harmony with observations. Specifically, they are consistent with the well-known observation that the pattern type is related to the geometry of the fingertip surface when fingerprint patterns are formed.

Dermatoglyphic peculiarities in children with oral clefts

In humans, the development of the primary palate and the lip is completed by the 7th week of intra uterine life and that of secondary palate by 12th week. The dermal ridges develop in relation to the volar pads, which are formed by the 6th week of gestation and reach maximum size between 12th and 13th weeks. This means that the genetic message contained in the genome--normal or abnormal is deciphered during this period and is also reflected by dermatoglyphics. Hence this study was done in order to observe the differences in dermatoglyphic patterns between the children with oral clefts and normal children and to determine the usefulness of dermatoglyphics in studying the genetic etiology of oral clefts. Dermatoglyphic data from 50 oral cleft children and 50 normal children were collected using the ink method and comparison was done between them. In the present study, we found an increase in the ulnar loop patterns on the distal phalanges of the ten fingers, an increase in the atd angle and an increase in the fluctuating asymmetry of the atd angle in the oral cleft children which indicates the degree of developmental instability of the oral cleft individual.

Comparative investigations of human and rat dermatoglyphics: palmar, plantar and digital pads and flexion creases.

The morphological features of the palmar, plantar and digital areas of the rat were studied and compared to the corresponding human traits. The location and the timing of appearance of the volar pads and flexion creases of human and rat fetuses were investigated to determine the feasibility of using rats as an experimental model for studying the factors influencing early development of the dermatoglyphics in humans. Comparisons between analogous developmental stages of human and rat fetuses demonstrate striking similarities in overall fetal development. However, marked differences between human and rat fetuses were found in the timing of developmental milestones and in some morphological features. Provided that these differences are taken into consideration, rats can serve as a useful experimental model in studies of the utility of the epidermal ridge configurations and flexion creases in medical disorders.

The nerve-dependency of Merkel cell proliferation in cultured human fetal glabrous skin.

Merkel cells are thought to function as slowly adapting mechanoreceptors and are known as targets for sensory nerves. However, the nerve-dependency of Merkel cells remains controversial. In this respect, some investigators have found interregional differences between hairy and glabrous skin and others have shown intraregional differences within denervated rat touch domes. Differences between species have also been reported. This study was performed to determine whether Merkel cells proliferate in vitro in the absence of the systemic factors, blood vessels and the intact nerves in human skin. Suspension organ culture was performed using fetal digits to investigate their in vitro proliferation. Merkel cells and cutaneous nerves were identified using antibodies to cytokeratin 20 and protein gene product 9.5 (PGP 9.5), respectively. Fetal digits of 56-82 day gestational age were cultured in serum free medium in a high O2 (45%) environment. Tissues were harvested before starting culture (D0) and 1, 4, 7, 14, 28 d after culture. Merkel cells were observed in the volar pads and dorsal nail matrices at D0. After 28 d of suspension organ culture, digits looked healthy structurally and the number of Merkel cells had increased. However, PGP 9.5-immunoreactive nerves were markedly diminished after 1 day of culture and almost disappeared after 4 days. Merkel cell proliferation in vitro suggested that Merkel cell development is probably nerve-independent in human fetal glabrous skin.

Micro-anatomy of the volar skin and interordinal relationships of primates.

Paleontological and molecular evidence have been employed to suggest that flying lemurs (Dermoptera) and primates form a monophyletic group, in sharp contrast with cranial and postcranial evidence indicating sister group relationships between flying lemurs and bats (Chiroptera). New evidence from the epidermis of the volar pads of primates, tree shrews, flying lemurs, bats, and other mammals was examined and mapped on to various hypotheses of archontan relationships. The micro-anatomy of the skin on the palm and sole of flying lemurs and bats differs fundamentally from that of tree shrews (Scandentia) and primates. The volar skin of flying lemurs and bats lacks the serial arrangement of papillary ridges and grooves ("fingerprints") found in primates, tree shrews, and many other mammals. Moreover, the junction between the epidermis and dermis in flying lemurs and bats is relatively flat and shows little or no development of the internal ridges that occur in primates and tree shrews. When mapped on to a set of cladograms of mammals currently allocated to the superorder Archonta, this new evidence does not support sister group relationships between flying lemurs and primates, regardless of the volar skin morphology that characterized the last common ancestor of Archonta. Micro-anatomical differences that distinguish the volar skin of flying lemurs and bats from that of primates and tree shrews reflect a profound dichotomy in the functional roles fulfilled by the extremities, which could be significant in a phylogenetic context.

Intraspecific Variation in the Vocalizations and Hand Pad Morphology of Southern Lesser Bush Babies (Galago moholi): A Comparison with G. senegalensis

Previous studies have shown the taxonomic value of vocal repertoires and hand (volar) pad characteristics in the classification of cryptic nocturnal primates such as bush babies. However, no study included quantitative comparisons within the geographical range of any one species. We investigated levels of intraspecific variation in calls and hand pad characteristics of the southern lesser bush baby (Galago moholi), using the northern lesser bush baby (Galago senegalensis) for interspecific comparisons. Examination of calls recorded from different regions along a transect of 1500 km across southern Africa revealed low levels of intraspecific variation in Galago moholi, whereas comparisons with homologous call-types in G. senegalensis revealed them to be significantly different. Volar pad measurements across the ranges of both species also showed low levels of intraspecific variation and relatively high interspecific variation. These findings demonstrate that vocal and volar pad characteristics can be used as consistent measures of difference between species that look almost identical. These methods provide a practical means of distinguishing between cryptic species, whether in the field, in captivity, or, in the case of volar pads, of preserved specimens.

Pads and flexion creases on the plantar surface of hammertoe mutant mouse (Hm).

The purpose of the present work was to determine the effects of the hereditary malformation of Hammertoe mutant mice (gene symbol Hm) on the surrounding morphological structures and, specifically, on the volar pads, i.e., the sites of the epidermal ridge patterns (dermatoglyphics). The hindlimbs of the wild-type (+/+) Hammertoe mice show no anomalies and their major pad and flexion crease configurations correspond to those of normal mice. The heterozygous (Hm/+) and homozygous (Hm/Hm) mice display a fusion of the interdigital tissues involving all digits with the exception of digit I. In Hm/Hm mice, this webbing extends to the distal phalanx and the markedly flexed digits form a shape resembling a hammer. In Hm/+ mice, the interdigital webbing does not extend as far and the digits show moderate flexion compared to those of Hm/Hm mice. Both Hm/Hm and Hm/+ have a rudimentary extra digit in the postaxial area of the hindlimbs. The ventral volar skin of the flexed digits is incompletely developed. The more posterior digits show the more severe camptodactyly. These aberrant configurations are related to the abnormal occurrence of the programmed cell death (PCD) in the interdigital zones II-IV and the proximal part of the postaxial margin during hindlimb development. They are limited to the pads on the plantar surface of the postaxial area; the preaxial area is not affected. As a result of a severe camptodactyly of digit V, its volar skin is shifted into the distal portion of the hypothenar area. This shifting affects the number, size, and location of the pads, especially of the hypothenar pad, resulting in varying pad configurations, such as a displacement of the distal and proximal components of the hypothenar pad, or a fusion of the two components of the hypothenar pad, leading to a reduced final pad number. These pad modifications are induced by the postaxial plantar surface shifting proximally and are not affected by the presence of an extra rudimentary digit. The pad modifications in Hammertoe mice with webbed digits and postaxial polydactyly resemble closely those of the previously studied mice with genetic preaxial polydactyly.

Volar adhesive pads of the feathertail glider, Acrobates pygmaeus (Marsupialia; Acrobatidae)

The feathertail glider (Acrobates pygmaeus) is a mouse-sized marsupial that can cling to and run on smooth vertical panes of glass. To understand this remarkable ability, a comparative histological study of pads on the volar surface of the pes and manus of four species of marsupials was completed. Acrobates pygmaeus and Cercartetus concinnus have well-developed volar pads that consist of epidermal ridge - sweat gland complexes. Such pads are less developed in Tarsipes rostratus and are not externally visible in Sminthopsis crassicaudata. In addition to its possible role in capillary adhesion, the epidermal ridge - sweat gland complex of A. pygmaeus has a unique epidermal histo-architecture. Here, the stratum corneum consists of horizontal rows of cell remnants that do not become flattened or adpressed to form a stratified squamous epithelium. It is proposed that the tall stratum corneum resists shear and compression that develop when the feathertail glider completes a glide.

The use of hand morphology in the taxonomy of galagos

Measurements of volar (hand) pad area were made for 244 specimens, representing 12 species and 4 genera of galagos (sub-family Galaginae). When corrected for body weight, statistically significant differences were identified, at both the genus and species levels in the areas of the volar pads. Most informative, in terms of taxonomic differences, were measurements of two of the five pads; interdigjtal pad number 4 and thenar pad number 5. Closely related species were distinguishable on the basis of these measurements. The thick-tailed galago (Otolemur crassicaudatus) was separate from Garnett's galago (O. garnettii) and the specific status of the silver greater galago (O. argentatus) was supported. Likewise, the two needle-clawed galagos (Euoticus elegantulus andE. pallidus), recently separated on mitochodrial DNA grounds, were found to differ significantly in their volar pad morphology. These studies show that comparative studies of volar hand pad morphology provide a novel approach to the re-assessment of galago taxonomy, and may be applicable also in taxonomic studies of other prosimian groups.