Influence of Body Posture and Gravitational Forces on Shear Wave Propagation in the Skin

Abstract

The body posture and gravitational forces govern in part the intrinsic skin tensile strength because they influence the orientation of the dermal fibre networks. Our objective was to assess changes in shear wave propagation in the skin according to the body posture and orientation of the gravitational forces. The study was performed in 30 middle-aged women with a normal body mass index. The Reviscometer^® was used to assess the mechanical wave propagation on the volar forearm in extension or flexion. Similar measurements were made on the supra-areolar region of the breast when the trunk was in the horizontal or vertical position. Four measurements were made in each of 4 directions at given angles with regard to the body axis. The device gave reproducible data. Shear wave propagation was influenced by the body posture. The intra-individual variability in shear wave velocity according to the directions of measurements increased when the tissues were in a relaxed position. Skin tensile anisotropy increased in a relaxed body posture. Shear wave propagation may be a convenient non-invasive tool to better identify the natural skin tension lines in the skin, thus refining the orientation of incision during cutaneous surgery.

Age- and body mass index-related changes in cutaneous shear wave velocity

“…The time the waves needs to travel from the transmitter to the receiver is the RRTM expressed in arbitrary units. The instrumental variability tested on human skin was lower than 14% (Nizet et al, 2001) while it averaged to 1.2% on a silicone gel.…”

“…The Reviscometer ® is a new device for measuring the shear wave velocity in the skin (Nizet et al, 2001). The speed of propagation of the acoustic wave on the skin surface is inversely proportional to the stiffness and density of the tissues (Potts et al, 1983(Potts et al, , 1984Davis et al, 1989;Vexler et al, 1999).…”

“…Resonance running time measurements (RRTM) were performed using an advanced prototype named Reviscometer ® RVM 600 (C + K Electronic, Cologne) (Nizet et al, 2001). The probe of the device contains two stylus sensors which are 2 mm apart.…”

“…These aspects have been studied so far using different instrumental methods based on distinct physical principles. Among them, the assessment of the velocity of elastic shear wave propagation represents a promising approach (Potts et al, 1983(Potts et al, , 1984Serup, 1985;Dorogi et al, 1986;Davis et al, 1989;Pereira et al, 1990;Mridha et al, 1992;McHugh et al, 1997;Enk et al, 1998;Vexler et al, 1999;Nizet et al, 2001). Indeed, the propagation of shear waves has been shown to change with age (Potts et al, 1983(Potts et al, , 1984Davis et al, 1989;Pereira et al, 1990).…”

Acetyl hexapeptide-3 in a cosmetic formulation acts on skin mechanical properties - clinical study

“…Such a finding suggests increased firmness or tensor effect, since the speed of shear wave propagation on the skin surface is directly proportional to its stiffness (Ruvolo, Stamatas, Kollias, 2007;Vexler, Polyansky, Gorodetsky, 1999). In rigid skin the time for wave spreading will be short, anisotropy and RRTM values smaller (Nizet, Pierard-Franchimont, Pierard, 2001;Verhaegen et al, 2010). Ruvolo, Stamatas and Kollias (2007) and Hermanns-Lê et al (2001) observed that while the minimum RRTM values remained fairly constant for the different age groups, the maximum RRTM values increased with age.…”