Influence of body posture and gravitational forces on shear wave propagation in the skin

The body posture and gravitational forces govern in part the intrinsic skin tensile strength because they influence the orientation of the dermal fibr e networks. Our objective was to assess changes in shear wave propagation i n the skin according to the body posture and orientation of the gravitation al forces. The study was performed in 30 middle-aged women with a normal bo dy mass index. The Reviscometer (R) was used to assess the mechanical wave propagation on the volar forearm in extension or flexion. Similar measureme nts 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 g ave reproducible data. Shear wave propagation was influenced by the body po sture. The intra-individual variability in shear wave velocity according to the directions of measurements increased when the tissues were in a relaxe d position. Skin tensile anisotropy increased in a relaxed body posture. Sh ear wave propagation may be a convenient non-invasive tool to better identi fy the natural skin tension lines in the skin, thus refining the orientatio n of incision during cutaneous surgery. Copyright (C) 2001 S. Karger AG, Ba sel.