Figure 1: Representative semithin cross-sections of an endoneurial area of the sural nerve digitized for morphometry (a). The same area is shown in (b) and (c), with the myelin sheaths marked in red (fiber mask) by the semiautomated (b) and automatic (c) methods. Note the “misdetection” of irregular fibers and artifacts by the automatic segmentation and the detection of the myelin sheath background pixels, even to the point of uniting two separate fibers. Toluidine blue stained, bars = 10 μm.