A selvedge (British English) is a self-finished edge of fabric. The selvages keep the fabric from unravelling or fraying. The selvages are a result of how the fabric is created.
Source: https://en.wikipedia.org/wiki/Selvage (derived 11-4-2016)

For me it is clear that this 'edge' is self-created, it outlines the form and identity. (Wikipedia also refers to: the print industry, where a selvedge is the excess area of a printed or perforated sheet of any material, such as the white border area of a sheet of stamps). Can we look at our skin as the bodily selvedge; the edge of our self?