Directional variation in extensibility of human skin in vivo

Gibson, T.; Stark, H.L.; Evans, John H.

doi:10.1016/0021-9290(69)90032-3

Cited by 83 publications

(30 citation statements)

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“…Thus, we have found a correlation between increased stiffness and fiber orientation along the axis of the strip. This is consistent with previous observations on the directional stiffness of collagen sheets (Gibson et al, 1969;Lanir and Fung, 1974) and suggests that, despite the diversity of orientation of fibers within a given region, local differences in collagen fiber orientation result in anisotropy of pericardial stiffness.…”

Section: Discussionsupporting

confidence: 81%

Mechanical and structural correlates of canine pericardium.

Wiegner¹,

Bing²,

Borg³

et al. 1981

Circulation Research

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SUMMARY We have assessed viscoelastic properties of pericardium within the physiological range of stresses and related mechanical behavior to fiber direction as defined by scanning electron microscopy. Stiffness, stress relaxation, and creep were measured in samples taken from the anterior surface of 14 canine pericardia. Stress-strain relations generally were not exponential; stiffness at a stress of 1 g/nun* ranged from 12.9 to 239 g/mm l during stretch and varied both from pericardium to pericardium and with the orientation of the strip within the sample (anisotropy). The strips exhibited hyst«retic behavior which was not proportional to rate of strain. Following a rapid increase in stress, creep averaged less than 1% and stress relaxation, 34%, in a 30-minute test period. The orientation of the strip with the greatest stiffness was consistent from pericardium to pericardium, and correlated with a layer of collagen fibers oriented along the major axis of the strip. Circ Res 49: 807-814, 1981 SOME previous studies of the properties of pericardial strips (Rabkin et al., 1974(Rabkin et al., , 1975 have applied large, non-physiological loads to the tissue in order to define such material properties as tensile strength (stress of failure). Others (Vito, 1979) have not taken into account orientation of the strips because of claimed isotropy of the pericardium (Hildebrandt et al., 1969). Finally, no studies have combined detailed analysis of mechanical properties with microscopic examination of the structures responsible for those properties. In the present study, we investigated the elastic and viscoelastic properties of the pericardium, particularly at low stresses, while avoiding high, non-physiological stresses. To relate pericardia! structure to physiology, mechanical properties were related to the orientation of the collagen fibers within the strips, visualized by scanning electron microscopy. Methods A circular sample of parietal pericardium approximately 3 cm in diameter was removed from the Received August 14, 1980; accepted for publication April 7, 1981 anterior surface of the heart of 14 dogs and maintained in oxygenated (95% 0 2 , 5% CO 2 ) Krebs-Henseleit solution at 37°C. Fatty tissue overlying the pericardium was dissected away if necessary. From one to four strips, approximately 2 x 13 mm, were cut from each section, for a total of 42 strips. Adjacent parallel strips were used to test the reproducibility of analysis of mechanical properties, and strips oriented to each other at 45° or 90°C were tested for isotropy of the pericardium. Spring clips were attached to the ends of the pericardial strips which then were studied in an apparatus usually used for isolated papillary muscle studies (Sulman et al., 1974; Wiegner and Bing, 1977) with a force range of 0-10 g. Quantization error was less than 20 mg for force and 5 /xm for length measurements. Length and width of the strips were measured with a Gaertner cathetometer and telescope. Length and force servosystems facilitated computer control of ...

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Section: Discussionsupporting

confidence: 81%

Mechanical and structural correlates of canine pericardium.

Wiegner¹,

Bing²,

Borg³

et al. 1981

Circulation Research

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“…Our literature review did not reveal any findings related to the orientation of Langer's lines in human fingerpad skin (Gibson et al, 1969). It is conceivable that the papillary ridges might be aligned with the Langer's lines if they exist in the fingerpad.…”

Section: Discussionmentioning

confidence: 82%

“…Some of these effects are strongly correlated with the Langer's lines (Ridge and Wright, 1966;Gibson et al, 1969;Stark, 1977). Some others are related to the body geometry.…”

Section: Discussionmentioning

confidence: 99%

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In vivo biomechanics of the fingerpad skin under local tangential traction

Wang

Hayward

2007

Journal of Biomechanics

139

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Small patches of fingerpad glabrous skin in human subjects were tested in vivo for their biomechanical properties under tangential loading and for large deformations. These conditions included stretching and shearing the skin at a length scale of 0.3 mm using an apparatus comprising a pair of piezoelectric benders arranged to increase the stiffness/free deflection tradeoff when compared to ordinary cantilevered benders. It was then possible to test the skin with up to 80% of tangential strain. With feedback control, it was also possible to create isotonic and isometric testing conditions. The results showed much variability across subjects and it was seen that the glabrous skin exhibited nonlinear stiffening in tangential traction. The skin was consistently more elastic across the ridges than along the ridges regardless of the location of the sample on the fingerpad. The skin behaved visco-elastically but relaxed about twice as fast than it crept. Finally, it was found that under large deformation, there was consistently an 80% of hysteretic loss for a wide range of loading conditions.

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“…Ever since the 19th century, surgeons have recognized the fact that this tension load is directional by observing that circular punctures in skin produce elliptical holes [4] . These lines, termed 'Langer's lines', represent the directions of the skin's maximum tension and have been identified over the whole body [5,6] . They are used as the preferred direction in which surgical incisions are made so that the tension across the wound is minimal.…”

Section: Introductionmentioning

confidence: 99%

Skin Viscoelasticity Displays Site- and Age-Dependent Angular Anisotropy

Ruvolo

Stamatas

Kollias

2007

Skin Pharmacol Physiol

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One of the dominant characteristics of skin aging is loss of elasticity. Although the changes in the mechanical properties of the skin over several decades of life are substantial, objective measurements have failed to capture their magnitude thus far. Moreover, the mechanical properties of the skin are not uniform in all directions, and there is a need to understand this angular anisotropy. In this work we present a methodology of documenting the angular anisotropy of skin elasticity with high sensitivity and dynamic range using the Reviscometer® RVM 600 (Courage & Khazaka Electronic GmbH, Cologne, Germany). The method is based on determining the directional dependence of the speed of an acoustic shear wave on the skin surface at intervals of 3°. Based on the angular distribution of the resonance running time, we define two parameters: the anisotropy and the angular dispersion width. We find that with increasing age the anisotropy increases, while the angular dispersion width decreases. The ratio of these values provides a sensitive parameter for the assessment of the directional behavior of the skin mechanical properties. This parameter provides a large effective dynamic range capable of demonstrating close to an order of magnitude differences in skin viscoelasticity from infants up to adults 75 years of age. Furthermore, we show that the direction of the angular anisotropy relates to the direction of the dermal cleavage lines as defined by Langer, indicating that the anisotropy of the mechanical properties of skin stems from structural parameters. Based on these results, we conclude that the proposed methodology is able to capture accurately the age-dependent changes of the mechanical properties of the skin and to demonstrate a structure-function relationship.

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Directional variation in extensibility of human skin in vivo

Cited by 83 publications

References 1 publication

Mechanical and structural correlates of canine pericardium.

Mechanical and structural correlates of canine pericardium.

In vivo biomechanics of the fingerpad skin under local tangential traction

Skin Viscoelasticity Displays Site- and Age-Dependent Angular Anisotropy

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