Fig 2. Define sample-specific models with segmented nerve images.

We segmented the nerve boundary (n.tif), the perineurium (either “Combined” (c.tif), or both “Inners” (i.tif) and “Outers” (o.tif), or only “Inners”), and a horizontal “Scale Bar” (s.tif) of known length from a micrograph of a human cervical vagus nerve stained selectively for perineurium. In this example, two fascicles have multiple inner traces for their single outer trace (i.e., “peanut” fascicles), which requires their perineurium to be meshed; conversely, the other fascicles have a single inner trace for each outer trace, in which case the perineurium can be either meshed or modeled with a thin layer approximation. The nerve cross section is modeled in the (x,y,0) plane and extruded into the +z direction for the length of the nerve.