Are Wet-Induced Wrinkled Fingers Primate Rain Treads?

Changizi, Mark A.; Weber, R. Neal; Kotecha, Ritesh; Palazzo, Joseph

doi:10.1159/000328223

Cited by 40 publications

(19 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It does not, however, show how this is accomplished. One possibility is that the wrinkles channel the evacuation of water from between the finger pad and the object, as suggested by the rain tread hypothesis [11]. Another possibility is that there are changes in skin properties, such as flexibility, adhesion or an increase in the friction coefficient, which all could improve performance under submerged conditions.…”

Section: Discussionmentioning

confidence: 99%

Water-induced finger wrinkles improve handling of wet objects

2013

View full text Add to dashboard Cite

Upon continued submersion in water, the glabrous skin on human hands and feet forms wrinkles. The formation of these wrinkles is known to be an active process, controlled by the autonomic nervous system. Such an active control suggests that these wrinkles may have an important function, but this function has not been clear. In this study, we show that submerged objects are handled more quickly with wrinkled fingers than with unwrinkled fingers, whereas wrinkles make no difference to manipulating dry objects. These findings support the hypothesis that water-induced finger wrinkles improve handling submerged objects and suggest that they may be an adaptation for handling objects in wet conditions.

show abstract

Section: Discussionmentioning

confidence: 99%

Water-induced finger wrinkles improve handling of wet objects

2013

View full text Add to dashboard Cite

show abstract

“…Understanding the role of the skin microstructure on its response to deformations has the potential to shed light on fundamental questions such as evolutionary aspects concerning the advantages provided by certain skin characteristics or functional abilities. For example, it was recently demonstrated that water-induced finger wrinkles in humans improved the handling of submerged objects (Kareklas et al, 2013), therefore confirming a possible evolutionary mechanical advantage for manipulating objects in submerged conditions (Changizi et al, 2011). An in-depth understanding of the structurefunction relationship of the skin also presents many opportunities for practical applications in the aforementioned industrial sectors besides the obvious applications in biomedical and health sciences where the coupling between mechanics and biology (i.e.…”

Section: Introductionmentioning

confidence: 90%

A mechanistic insight into the mechanical role of the stratum corneum during stretching and compression of the skin

Leyva-Mendivil

Page

Bressloff

et al. 2015

Journal of the Mechanical Behavior of Biomedical Materials

109

View full text Add to dashboard Cite

A mechanistic insight into the mechanical role of the stratum corneum during stretching and compression of the skin. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.www.elsevier.com/locate/jmbbm 1 A mechanistic insight into the mechanical role of the stratum corneum during stretching and compression of the skin. AbstractThe study of skin biophysics has largely been driven by consumer goods, biomedical and cosmetic industries which aim to design products that efficiently interact with the skin and/or modify its biophysical properties for health or cosmetic benefits. The skin is a hierarchical biological structure featuring several layers with their own distinct geometry and mechanical properties. Up to now, no computational models of the skin have simultaneously accounted for these geometrical and material characteristics to study their complex biomechanical interactions under particular macroscopic deformation modes.The goal of this study was, therefore, to develop a robust methodology combining histological sections of human skin, image-processing and finite element techniques to address fundamental questions about skin mechanics and, more particularly, about how macroscopic strains are transmitted and modulated through the epidermis and dermis. The work hypothesis was that, as skin deforms under macroscopic loads, the stratum corneum does not experience significant strains but rather folds/unfolds during skin extension/compression.A sample of fresh human mid-back skin was processed for wax histology. Sections were stained and photographed by optical microscopy. The multiple images were stitched together to produce a larger region of interest and segmented to extract the geometry of the stratum corneum, viable epidermis and dermis. From the segmented structures a 2D finite element mesh of the skin composite model was created and geometrically non-linear plane-strain finite element analyses were conducted to study the sensitivity of the model to variations in mechanical properties.The hybrid experimental-computational methodology has offered valuable insights into the simulated mechanics of the skin, and that of the stratum corneum in particular, by providing qualitative and quantitative information on strain magnitude and distribution. Through a complex non-linear interplay, the geometry and mechanical characteristics of the skin layers (and their relative balance), play a critical role in conditioning the skin mechanical response to macroscopic in-plane compression and extension. Topographical features of the skin surface such as furrows were shown to act as an efficient means to deflec...

show abstract

“…It is also possible to control the formation of wrinkles using water temperature, tonicity and the depth of immersion. The theory of wrinkles as an evolutionary advantage for primates handling objects in wet environments (20,21) seems implausible.…”

Section: Discussionmentioning

confidence: 99%

Free flow of sweat due to loss of surface tension at sweat droplets causes water-induced skin wrinkling

Marasakatla¹,

Marasakatla²

2013

Preprint

View full text Add to dashboard Cite

Water immersion skin wrinkling has long been used as a test for sympathetic nerve function. However, the cause of underlying mechanism remained elusive. In this article, we theoretically investigate a possible cause of the phenomenon by taking various properties of sweating into consideration. The pressure exerted by the surface tension of sweat droplets counterbalances the secretory pressure of sweat glands at the pore. When a hand is immersed in water, sweat droplets easily merge with the water, causing the pressure to drop at the pore. Our calculations, using earlier measurements of secretory pressure, show that the water pressure at the sweat pore will be less than the secretory pressure of sweat glands when the hand is immersed at a shallow depth. The resulting pressure imbalance enables the sweat to flow freely into the water. We believe that there will be an initial vasodilation to feed the excess generation of sweat. Sweat flow continues as long as there is blood flow to the hand. To prevent excessive loss of sweat from the body and to maintain homeostasis, sympathetic nerves trigger vasoconstriction to reduce the blood flow to the hand. The overlying skin wrinkles due to loss of volume under the skin. It is possible that denerved fingers remain in the vasodilation state during immersion due to a lack of sympathetic nerve function.

show abstract

Are Wet-Induced Wrinkled Fingers Primate Rain Treads?

Cited by 40 publications

References 31 publications

Water-induced finger wrinkles improve handling of wet objects

Water-induced finger wrinkles improve handling of wet objects

A mechanistic insight into the mechanical role of the stratum corneum during stretching and compression of the skin

Free flow of sweat due to loss of surface tension at sweat droplets causes water-induced skin wrinkling

Contact Info

Product

Resources

About